Chapter 5. Develop 5.1. Serverless applications Serverless applications are created and deployed as Kubernetes services, defined by a route and a configuration, and contained in a YAML file. To deploy a serverless application using OpenShift Serverless, you must create a Knative Service object. Example Knative Service object YAML file apiVersion: serving.knative.dev/v1 kind: Service metadata: name: hello 1 namespace: default 2 spec: template: spec: containers: - image: docker.io/openshift/hello-openshift 3 env: - name: RESPONSE 4 value: "Hello Serverless!" 1 The name of the application. 2 The namespace the application uses. 3 The image of the application. 4 The environment variable printed out by the sample application. You can create a serverless application by using one of the following methods: Create a Knative service from the OpenShift Container Platform web console. See the documentation about Creating applications using the Developer perspective . Create a Knative service by using the Knative ( kn ) CLI. Create and apply a Knative Service object as a YAML file, by using the oc CLI. 5.1.1. Creating serverless applications by using the Knative CLI Using the Knative ( kn ) CLI to create serverless applications provides a more streamlined and intuitive user interface over modifying YAML files directly. You can use the kn service create command to create a basic serverless application. Prerequisites OpenShift Serverless Operator and Knative Serving are installed on your cluster. You have installed the Knative ( kn ) CLI. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. Procedure Create a Knative service: USD kn service create <service-name> --image <image> --tag <tag-value> Where: --image is the URI of the image for the application. --tag is an optional flag that can be used to add a tag to the initial revision that is created with the service. Example command USD kn service create event-display \ --image quay.io/openshift-knative/knative-eventing-sources-event-display:latest Example output Creating service 'event-display' in namespace 'default': 0.271s The Route is still working to reflect the latest desired specification. 0.580s Configuration "event-display" is waiting for a Revision to become ready. 3.857s ... 3.861s Ingress has not yet been reconciled. 4.270s Ready to serve. Service 'event-display' created with latest revision 'event-display-bxshg-1' and URL: http://event-display-default.apps-crc.testing 5.1.2. Creating a service using offline mode You can execute kn service commands in offline mode, so that no changes happen on the cluster, and instead the service descriptor file is created on your local machine. After the descriptor file is created, you can modify the file before propagating changes to the cluster. Important The offline mode of the Knative CLI is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process. For more information about the support scope of Red Hat Technology Preview features, see https://access.redhat.com/support/offerings/techpreview/ . Prerequisites OpenShift Serverless Operator and Knative Serving are installed on your cluster. You have installed the Knative ( kn ) CLI. Procedure In offline mode, create a local Knative service descriptor file: USD kn service create event-display \ --image quay.io/openshift-knative/knative-eventing-sources-event-display:latest \ --target ./ \ --namespace test Example output Service 'event-display' created in namespace 'test'. The --target ./ flag enables offline mode and specifies ./ as the directory for storing the new directory tree. If you do not specify an existing directory, but use a filename, such as --target my-service.yaml , then no directory tree is created. Instead, only the service descriptor file my-service.yaml is created in the current directory. The filename can have the .yaml , .yml , or .json extension. Choosing .json creates the service descriptor file in the JSON format. The --namespace test option places the new service in the test namespace. If you do not use --namespace , and you are logged in to an OpenShift cluster, the descriptor file is created in the current namespace. Otherwise, the descriptor file is created in the default namespace. Examine the created directory structure: USD tree ./ Example output ./ └── test └── ksvc └── event-display.yaml 2 directories, 1 file The current ./ directory specified with --target contains the new test/ directory that is named after the specified namespace. The test/ directory contains the ksvc directory, named after the resource type. The ksvc directory contains the descriptor file event-display.yaml , named according to the specified service name. Examine the generated service descriptor file: USD cat test/ksvc/event-display.yaml Example output apiVersion: serving.knative.dev/v1 kind: Service metadata: creationTimestamp: null name: event-display namespace: test spec: template: metadata: annotations: client.knative.dev/user-image: quay.io/openshift-knative/knative-eventing-sources-event-display:latest creationTimestamp: null spec: containers: - image: quay.io/openshift-knative/knative-eventing-sources-event-display:latest name: "" resources: {} status: {} List information about the new service: USD kn service describe event-display --target ./ --namespace test Example output Name: event-display Namespace: test Age: URL: Revisions: Conditions: OK TYPE AGE REASON The --target ./ option specifies the root directory for the directory structure containing namespace subdirectories. Alternatively, you can directly specify a YAML or JSON filename with the --target option. The accepted file extensions are .yaml , .yml , and .json . The --namespace option specifies the namespace, which communicates to kn the subdirectory that contains the necessary service descriptor file. If you do not use --namespace , and you are logged in to an OpenShift cluster, kn searches for the service in the subdirectory that is named after the current namespace. Otherwise, kn searches in the default/ subdirectory. Use the service descriptor file to create the service on the cluster: USD kn service create -f test/ksvc/event-display.yaml Example output Creating service 'event-display' in namespace 'test': 0.058s The Route is still working to reflect the latest desired specification. 0.098s ... 0.168s Configuration "event-display" is waiting for a Revision to become ready. 23.377s ... 23.419s Ingress has not yet been reconciled. 23.534s Waiting for load balancer to be ready 23.723s Ready to serve. Service 'event-display' created to latest revision 'event-display-00001' is available at URL: http://event-display-test.apps.example.com 5.1.3. Creating serverless applications using YAML Creating Knative resources by using YAML files uses a declarative API, which enables you to describe applications declaratively and in a reproducible manner. To create a serverless application by using YAML, you must create a YAML file that defines a Knative Service object, then apply it by using oc apply . After the service is created and the application is deployed, Knative creates an immutable revision for this version of the application. Knative also performs network programming to create a route, ingress, service, and load balancer for your application and automatically scales your pods up and down based on traffic. Prerequisites OpenShift Serverless Operator and Knative Serving are installed on your cluster. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. Install the OpenShift CLI ( oc ). Procedure Create a YAML file containing the following sample code: apiVersion: serving.knative.dev/v1 kind: Service metadata: name: event-delivery namespace: default spec: template: spec: containers: - image: quay.io/openshift-knative/knative-eventing-sources-event-display:latest env: - name: RESPONSE value: "Hello Serverless!" Navigate to the directory where the YAML file is contained, and deploy the application by applying the YAML file: USD oc apply -f <filename> 5.1.4. Verifying your serverless application deployment To verify that your serverless application has been deployed successfully, you must get the application URL created by Knative, and then send a request to that URL and observe the output. OpenShift Serverless supports the use of both HTTP and HTTPS URLs, however the output from oc get ksvc always prints URLs using the http:// format. Prerequisites OpenShift Serverless Operator and Knative Serving are installed on your cluster. You have installed the oc CLI. You have created a Knative service. Prerequisites Install the OpenShift CLI ( oc ). Procedure Find the application URL: USD oc get ksvc <service_name> Example output NAME URL LATESTCREATED LATESTREADY READY REASON event-delivery http://event-delivery-default.example.com event-delivery-4wsd2 event-delivery-4wsd2 True Make a request to your cluster and observe the output. Example HTTP request USD curl http://event-delivery-default.example.com Example HTTPS request USD curl https://event-delivery-default.example.com Example output Hello Serverless! Optional. If you receive an error relating to a self-signed certificate in the certificate chain, you can add the --insecure flag to the curl command to ignore the error: USD curl https://event-delivery-default.example.com --insecure Example output Hello Serverless! Important Self-signed certificates must not be used in a production deployment. This method is only for testing purposes. Optional. If your OpenShift Container Platform cluster is configured with a certificate that is signed by a certificate authority (CA) but not yet globally configured for your system, you can specify this with the curl command. The path to the certificate can be passed to the curl command by using the --cacert flag: USD curl https://event-delivery-default.example.com --cacert <file> Example output Hello Serverless! 5.1.5. Interacting with a serverless application using HTTP2 and gRPC OpenShift Serverless supports only insecure or edge-terminated routes. Insecure or edge-terminated routes do not support HTTP2 on OpenShift Container Platform. These routes also do not support gRPC because gRPC is transported by HTTP2. If you use these protocols in your application, you must call the application using the ingress gateway directly. To do this you must find the ingress gateway's public address and the application's specific host. Important This method needs to expose Kourier Gateway using the LoadBalancer service type. You can configure this by adding the following YAML to your KnativeServing custom resource definition (CRD): ... spec: ingress: kourier: service-type: LoadBalancer ... Prerequisites OpenShift Serverless Operator and Knative Serving are installed on your cluster. Install the OpenShift CLI ( oc ). You have created a Knative service. Procedure Find the application host. See the instructions in Verifying your serverless application deployment . Find the ingress gateway's public address: USD oc -n knative-serving-ingress get svc kourier Example output NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kourier LoadBalancer 172.30.51.103 a83e86291bcdd11e993af02b7a65e514-33544245.us-east-1.elb.amazonaws.com 80:31380/TCP,443:31390/TCP 67m The public address is surfaced in the EXTERNAL-IP field, and in this case is a83e86291bcdd11e993af02b7a65e514-33544245.us-east-1.elb.amazonaws.com . Manually set the host header of your HTTP request to the application's host, but direct the request itself against the public address of the ingress gateway. USD curl -H "Host: hello-default.example.com" a83e86291bcdd11e993af02b7a65e514-33544245.us-east-1.elb.amazonaws.com Example output Hello Serverless! You can also make a gRPC request by setting the authority to the application's host, while directing the request against the ingress gateway directly: grpc.Dial( "a83e86291bcdd11e993af02b7a65e514-33544245.us-east-1.elb.amazonaws.com:80", grpc.WithAuthority("hello-default.example.com:80"), grpc.WithInsecure(), ) Note Ensure that you append the respective port, 80 by default, to both hosts as shown in the example. 5.1.6. Enabling communication with Knative applications on a cluster with restrictive network policies If you are using a cluster that multiple users have access to, your cluster might use network policies to control which pods, services, and namespaces can communicate with each other over the network. If your cluster uses restrictive network policies, it is possible that Knative system pods are not able to access your Knative application. For example, if your namespace has the following network policy, which denies all requests, Knative system pods cannot access your Knative application: Example NetworkPolicy object that denies all requests to the namespace kind: NetworkPolicy apiVersion: networking.k8s.io/v1 metadata: name: deny-by-default namespace: example-namespace spec: podSelector: ingress: [] To allow access to your applications from Knative system pods, you must add a label to each of the Knative system namespaces, and then create a NetworkPolicy object in your application namespace that allows access to the namespace for other namespaces that have this label. Important A network policy that denies requests to non-Knative services on your cluster still prevents access to these services. However, by allowing access from Knative system namespaces to your Knative application, you are allowing access to your Knative application from all namespaces in the cluster. If you do not want to allow access to your Knative application from all namespaces on the cluster, you might want to use JSON Web Token authentication for Knative services instead. JSON Web Token authentication for Knative services requires Service Mesh. Prerequisites Install the OpenShift CLI ( oc ). OpenShift Serverless Operator and Knative Serving are installed on your cluster. Procedure Add the knative.openshift.io/system-namespace=true label to each Knative system namespace that requires access to your application: Label the knative-serving namespace: USD oc label namespace knative-serving knative.openshift.io/system-namespace=true Label the knative-serving-ingress namespace: USD oc label namespace knative-serving-ingress knative.openshift.io/system-namespace=true Label the knative-eventing namespace: USD oc label namespace knative-eventing knative.openshift.io/system-namespace=true Label the knative-kafka namespace: USD oc label namespace knative-kafka knative.openshift.io/system-namespace=true Create a NetworkPolicy object in your application namespace to allow access from namespaces with the knative.openshift.io/system-namespace label: Example NetworkPolicy object apiVersion: networking.k8s.io/v1 kind: NetworkPolicy metadata: name: <network_policy_name> 1 namespace: <namespace> 2 spec: ingress: - from: - namespaceSelector: matchLabels: knative.openshift.io/system-namespace: "true" podSelector: {} policyTypes: - Ingress 1 Provide a name for your network policy. 2 The namespace where your application exists. 5.1.7. Configuring init containers Init containers are specialized containers that are run before application containers in a pod. They are generally used to implement initialization logic for an application, which may include running setup scripts or downloading required configurations. Note Init containers may cause longer application start-up times and should be used with caution for serverless applications, which are expected to scale up and down frequently. Multiple init containers are supported in a single Knative service spec. Knative provides a default, configurable naming template if a template name is not provided. The init containers template can be set by adding an appropriate value in a Knative Service object spec. Prerequisites OpenShift Serverless Operator and Knative Serving are installed on your cluster. Before you can use init containers for Knative services, an administrator must add the kubernetes.podspec-init-containers flag to the KnativeServing custom resource (CR). See the OpenShift Serverless "Global configuration" documentation for more information. Procedure Add the initContainers spec to a Knative Service object: Example service spec apiVersion: serving.knative.dev/v1 kind: Service ... spec: template: spec: initContainers: - imagePullPolicy: IfNotPresent 1 image: <image_uri> 2 volumeMounts: 3 - name: data mountPath: /data ... 1 The image pull policy when the image is downloaded. 2 The URI for the init container image. 3 The location where volumes are mounted within the container file system. 5.1.8. HTTPS redirection per service You can enable or disable HTTPS redirection for a service by configuring the networking.knative.dev/http-option annotation. The following example shows how you can use this annotation in a Knative Service YAML object: apiVersion: serving.knative.dev/v1 kind: Service metadata: name: example namespace: default annotations: networking.knative.dev/http-option: "redirected" spec: ... 5.1.9. Additional resources Knative Serving CLI commands Configuring JSON Web Token authentication for Knative services 5.2. Autoscaling Knative Serving provides automatic scaling, or autoscaling , for applications to match incoming demand. For example, if an application is receiving no traffic, and scale-to-zero is enabled, Knative Serving scales the application down to zero replicas. If scale-to-zero is disabled, the application is scaled down to the minimum number of replicas configured for applications on the cluster. Replicas can also be scaled up to meet demand if traffic to the application increases. Autoscaling settings for Knative services can be global settings that are configured by cluster administrators, or per-revision settings that are configured for individual services. You can modify per-revision settings for your services by using the OpenShift Container Platform web console, by modifying the YAML file for your service, or by using the Knative ( kn ) CLI. Note Any limits or targets that you set for a service are measured against a single instance of your application. For example, setting the target annotation to 50 configures the autoscaler to scale the application so that each revision handles 50 requests at a time. 5.2.1. Scale bounds Scale bounds determine the minimum and maximum numbers of replicas that can serve an application at any given time. You can set scale bounds for an application to help prevent cold starts or control computing costs. 5.2.1.1. Minimum scale bounds The minimum number of replicas that can serve an application is determined by the min-scale annotation. If scale to zero is not enabled, the min-scale value defaults to 1 . The min-scale value defaults to 0 replicas if the following conditions are met: The min-scale annotation is not set Scaling to zero is enabled The class KPA is used Example service spec with min-scale annotation apiVersion: serving.knative.dev/v1 kind: Service metadata: name: example-service namespace: default spec: template: metadata: annotations: autoscaling.knative.dev/min-scale: "0" ... 5.2.1.1.1. Setting the min-scale annotation by using the Knative CLI Using the Knative ( kn ) CLI to set the min-scale annotation provides a more streamlined and intuitive user interface over modifying YAML files directly. You can use the kn service command with the --scale-min flag to create or modify the min-scale value for a service. Prerequisites Knative Serving is installed on the cluster. You have installed the Knative ( kn ) CLI. Procedure Set the minimum number of replicas for the service by using the --scale-min flag: USD kn service create <service_name> --image <image_uri> --scale-min <integer> Example command USD kn service create example-service --image quay.io/openshift-knative/knative-eventing-sources-event-display:latest --scale-min 2 5.2.1.2. Maximum scale bounds The maximum number of replicas that can serve an application is determined by the max-scale annotation. If the max-scale annotation is not set, there is no upper limit for the number of replicas created. Example service spec with max-scale annotation apiVersion: serving.knative.dev/v1 kind: Service metadata: name: example-service namespace: default spec: template: metadata: annotations: autoscaling.knative.dev/max-scale: "10" ... 5.2.1.2.1. Setting the max-scale annotation by using the Knative CLI Using the Knative ( kn ) CLI to set the max-scale annotation provides a more streamlined and intuitive user interface over modifying YAML files directly. You can use the kn service command with the --scale-max flag to create or modify the max-scale value for a service. Prerequisites Knative Serving is installed on the cluster. You have installed the Knative ( kn ) CLI. Procedure Set the maximum number of replicas for the service by using the --scale-max flag: USD kn service create <service_name> --image <image_uri> --scale-max <integer> Example command USD kn service create example-service --image quay.io/openshift-knative/knative-eventing-sources-event-display:latest --scale-max 10 5.2.2. Concurrency Concurrency determines the number of simultaneous requests that can be processed by each replica of an application at any given time. Concurrency can be configured as a soft limit or a hard limit : A soft limit is a targeted requests limit, rather than a strictly enforced bound. For example, if there is a sudden burst of traffic, the soft limit target can be exceeded. A hard limit is a strictly enforced upper bound requests limit. If concurrency reaches the hard limit, surplus requests are buffered and must wait until there is enough free capacity to execute the requests. Important Using a hard limit configuration is only recommended if there is a clear use case for it with your application. Having a low, hard limit specified may have a negative impact on the throughput and latency of an application, and might cause cold starts. Adding a soft target and a hard limit means that the autoscaler targets the soft target number of concurrent requests, but imposes a hard limit of the hard limit value for the maximum number of requests. If the hard limit value is less than the soft limit value, the soft limit value is tuned down, because there is no need to target more requests than the number that can actually be handled. 5.2.2.1. Configuring a soft concurrency target A soft limit is a targeted requests limit, rather than a strictly enforced bound. For example, if there is a sudden burst of traffic, the soft limit target can be exceeded. You can specify a soft concurrency target for your Knative service by setting the autoscaling.knative.dev/target annotation in the spec, or by using the kn service command with the correct flags. Procedure Optional: Set the autoscaling.knative.dev/target annotation for your Knative service in the spec of the Service custom resource: Example service spec apiVersion: serving.knative.dev/v1 kind: Service metadata: name: example-service namespace: default spec: template: metadata: annotations: autoscaling.knative.dev/target: "200" Optional: Use the kn service command to specify the --concurrency-target flag: USD kn service create <service_name> --image <image_uri> --concurrency-target <integer> Example command to create a service with a concurrency target of 50 requests USD kn service create example-service --image quay.io/openshift-knative/knative-eventing-sources-event-display:latest --concurrency-target 50 5.2.2.2. Configuring a hard concurrency limit A hard concurrency limit is a strictly enforced upper bound requests limit. If concurrency reaches the hard limit, surplus requests are buffered and must wait until there is enough free capacity to execute the requests. You can specify a hard concurrency limit for your Knative service by modifying the containerConcurrency spec, or by using the kn service command with the correct flags. Procedure Optional: Set the containerConcurrency spec for your Knative service in the spec of the Service custom resource: Example service spec apiVersion: serving.knative.dev/v1 kind: Service metadata: name: example-service namespace: default spec: template: spec: containerConcurrency: 50 The default value is 0 , which means that there is no limit on the number of simultaneous requests that are permitted to flow into one replica of the service at a time. A value greater than 0 specifies the exact number of requests that are permitted to flow into one replica of the service at a time. This example would enable a hard concurrency limit of 50 requests. Optional: Use the kn service command to specify the --concurrency-limit flag: USD kn service create <service_name> --image <image_uri> --concurrency-limit <integer> Example command to create a service with a concurrency limit of 50 requests USD kn service create example-service --image quay.io/openshift-knative/knative-eventing-sources-event-display:latest --concurrency-limit 50 5.2.2.3. Concurrency target utilization This value specifies the percentage of the concurrency limit that is actually targeted by the autoscaler. This is also known as specifying the hotness at which a replica runs, which enables the autoscaler to scale up before the defined hard limit is reached. For example, if the containerConcurrency value is set to 10, and the target-utilization-percentage value is set to 70 percent, the autoscaler creates a new replica when the average number of concurrent requests across all existing replicas reaches 7. Requests numbered 7 to 10 are still sent to the existing replicas, but additional replicas are started in anticipation of being required after the containerConcurrency value is reached. Example service configured using the target-utilization-percentage annotation apiVersion: serving.knative.dev/v1 kind: Service metadata: name: example-service namespace: default spec: template: metadata: annotations: autoscaling.knative.dev/target-utilization-percentage: "70" ... 5.3. Traffic management In a Knative application, traffic can be managed by creating a traffic split. A traffic split is configured as part of a route, which is managed by a Knative service. Configuring a route allows requests to be sent to different revisions of a service. This routing is determined by the traffic spec of the Service object. A traffic spec declaration consists of one or more revisions, each responsible for handling a portion of the overall traffic. The percentages of traffic routed to each revision must add up to 100%, which is ensured by a Knative validation. The revisions specified in a traffic spec can either be a fixed, named revision, or can point to the "latest" revision, which tracks the head of the list of all revisions for the service. The "latest" revision is a type of floating reference that updates if a new revision is created. Each revision can have a tag attached that creates an additional access URL for that revision. The traffic spec can be modified by: Editing the YAML of a Service object directly. Using the Knative ( kn ) CLI --traffic flag. Using the OpenShift Container Platform web console. When you create a Knative service, it does not have any default traffic spec settings. 5.3.1. Traffic spec examples The following example shows a traffic spec where 100% of traffic is routed to the latest revision of the service. Under status , you can see the name of the latest revision that latestRevision resolves to: apiVersion: serving.knative.dev/v1 kind: Service metadata: name: example-service namespace: default spec: ... traffic: - latestRevision: true percent: 100 status: ... traffic: - percent: 100 revisionName: example-service The following example shows a traffic spec where 100% of traffic is routed to the revision tagged as current , and the name of that revision is specified as example-service . The revision tagged as latest is kept available, even though no traffic is routed to it: apiVersion: serving.knative.dev/v1 kind: Service metadata: name: example-service namespace: default spec: ... traffic: - tag: current revisionName: example-service percent: 100 - tag: latest latestRevision: true percent: 0 The following example shows how the list of revisions in the traffic spec can be extended so that traffic is split between multiple revisions. This example sends 50% of traffic to the revision tagged as current , and 50% of traffic to the revision tagged as candidate . The revision tagged as latest is kept available, even though no traffic is routed to it: apiVersion: serving.knative.dev/v1 kind: Service metadata: name: example-service namespace: default spec: ... traffic: - tag: current revisionName: example-service-1 percent: 50 - tag: candidate revisionName: example-service-2 percent: 50 - tag: latest latestRevision: true percent: 0 5.3.2. Knative CLI traffic management flags The Knative ( kn ) CLI supports traffic operations on the traffic block of a service as part of the kn service update command. The following table displays a summary of traffic splitting flags, value formats, and the operation the flag performs. The Repetition column denotes whether repeating the particular value of flag is allowed in a kn service update command. Flag Value(s) Operation Repetition --traffic RevisionName=Percent Gives Percent traffic to RevisionName Yes --traffic Tag=Percent Gives Percent traffic to the revision having Tag Yes --traffic @latest=Percent Gives Percent traffic to the latest ready revision No --tag RevisionName=Tag Gives Tag to RevisionName Yes --tag @latest=Tag Gives Tag to the latest ready revision No --untag Tag Removes Tag from revision Yes 5.3.2.1. Multiple flags and order precedence All traffic-related flags can be specified using a single kn service update command. kn defines the precedence of these flags. The order of the flags specified when using the command is not taken into account. The precedence of the flags as they are evaluated by kn are: --untag : All the referenced revisions with this flag are removed from the traffic block. --tag : Revisions are tagged as specified in the traffic block. --traffic : The referenced revisions are assigned a portion of the traffic split. You can add tags to revisions and then split traffic according to the tags you have set. 5.3.2.2. Custom URLs for revisions Assigning a --tag flag to a service by using the kn service update command creates a custom URL for the revision that is created when you update the service. The custom URL follows the pattern https://<tag>-<service_name>-<namespace>.<domain> or http://<tag>-<service_name>-<namespace>.<domain> . The --tag and --untag flags use the following syntax: Require one value. Denote a unique tag in the traffic block of the service. Can be specified multiple times in one command. 5.3.2.2.1. Example: Assign a tag to a revision The following example assigns the tag latest to a revision named example-revision : USD kn service update <service_name> --tag @latest=example-tag 5.3.2.2.2. Example: Remove a tag from a revision You can remove a tag to remove the custom URL, by using the --untag flag. Note If a revision has its tags removed, and it is assigned 0% of the traffic, the revision is removed from the traffic block entirely. The following command removes all tags from the revision named example-revision : USD kn service update <service_name> --untag example-tag 5.3.3. Creating a traffic split by using the Knative CLI Using the Knative ( kn ) CLI to create traffic splits provides a more streamlined and intuitive user interface over modifying YAML files directly. You can use the kn service update command to split traffic between revisions of a service. Prerequisites The OpenShift Serverless Operator and Knative Serving are installed on your cluster. You have installed the Knative ( kn ) CLI. You have created a Knative service. Procedure Specify the revision of your service and what percentage of traffic you want to route to it by using the --traffic tag with a standard kn service update command: Example command USD kn service update <service_name> --traffic <revision>=<percentage> Where: <service_name> is the name of the Knative service that you are configuring traffic routing for. <revision> is the revision that you want to configure to receive a percentage of traffic. You can either specify the name of the revision, or a tag that you assigned to the revision by using the --tag flag. <percentage> is the percentage of traffic that you want to send to the specified revision. Optional: The --traffic flag can be specified multiple times in one command. For example, if you have a revision tagged as @latest and a revision named stable , you can specify the percentage of traffic that you want to split to each revision as follows: Example command USD kn service update example-service --traffic @latest=20,stable=80 If you have multiple revisions and do not specify the percentage of traffic that should be split to the last revision, the --traffic flag can calculate this automatically. For example, if you have a third revision named example , and you use the following command: Example command USD kn service update example-service --traffic @latest=10,stable=60 The remaining 30% of traffic is split to the example revision, even though it was not specified. 5.3.4. Managing traffic between revisions by using the OpenShift Container Platform web console After you create a serverless application, the application is displayed in the Topology view of the Developer perspective in the OpenShift Container Platform web console. The application revision is represented by the node, and the Knative service is indicated by a quadrilateral around the node. Any new change in the code or the service configuration creates a new revision, which is a snapshot of the code at a given time. For a service, you can manage the traffic between the revisions of the service by splitting and routing it to the different revisions as required. Prerequisites The OpenShift Serverless Operator and Knative Serving are installed on your cluster. You have logged in to the OpenShift Container Platform web console. Procedure To split traffic between multiple revisions of an application in the Topology view: Click the Knative service to see its overview in the side panel. Click the Resources tab, to see a list of Revisions and Routes for the service. Figure 5.1. Serverless application Click the service, indicated by the S icon at the top of the side panel, to see an overview of the service details. Click the YAML tab and modify the service configuration in the YAML editor, and click Save . For example, change the timeoutseconds from 300 to 301 . This change in the configuration triggers a new revision. In the Topology view, the latest revision is displayed and the Resources tab for the service now displays the two revisions. In the Resources tab, click Set Traffic Distribution to see the traffic distribution dialog box: Add the split traffic percentage portion for the two revisions in the Splits field. Add tags to create custom URLs for the two revisions. Click Save to see two nodes representing the two revisions in the Topology view. Figure 5.2. Serverless application revisions 5.3.5. Routing and managing traffic by using a blue-green deployment strategy You can safely reroute traffic from a production version of an app to a new version, by using a blue-green deployment strategy . Prerequisites The OpenShift Serverless Operator and Knative Serving are installed on the cluster. Install the OpenShift CLI ( oc ). Procedure Create and deploy an app as a Knative service. Find the name of the first revision that was created when you deployed the service, by viewing the output from the following command: USD oc get ksvc <service_name> -o=jsonpath='{.status.latestCreatedRevisionName}' Example command USD oc get ksvc example-service -o=jsonpath='{.status.latestCreatedRevisionName}' Example output USD example-service-00001 Add the following YAML to the service spec to send inbound traffic to the revision: ... spec: traffic: - revisionName: <first_revision_name> percent: 100 # All traffic goes to this revision ... Verify that you can view your app at the URL output you get from running the following command: USD oc get ksvc <service_name> Deploy a second revision of your app by modifying at least one field in the template spec of the service and redeploying it. For example, you can modify the image of the service, or an env environment variable. You can redeploy the service by applying the service YAML file, or by using the kn service update command if you have installed the Knative ( kn ) CLI. Find the name of the second, latest revision that was created when you redeployed the service, by running the command: USD oc get ksvc <service_name> -o=jsonpath='{.status.latestCreatedRevisionName}' At this point, both the first and second revisions of the service are deployed and running. Update your existing service to create a new, test endpoint for the second revision, while still sending all other traffic to the first revision: Example of updated service spec with test endpoint ... spec: traffic: - revisionName: <first_revision_name> percent: 100 # All traffic is still being routed to the first revision - revisionName: <second_revision_name> percent: 0 # No traffic is routed to the second revision tag: v2 # A named route ... After you redeploy this service by reapplying the YAML resource, the second revision of the app is now staged. No traffic is routed to the second revision at the main URL, and Knative creates a new service named v2 for testing the newly deployed revision. Get the URL of the new service for the second revision, by running the following command: USD oc get ksvc <service_name> --output jsonpath="{.status.traffic[*].url}" You can use this URL to validate that the new version of the app is behaving as expected before you route any traffic to it. Update your existing service again, so that 50% of traffic is sent to the first revision, and 50% is sent to the second revision: Example of updated service spec splitting traffic 50/50 between revisions ... spec: traffic: - revisionName: <first_revision_name> percent: 50 - revisionName: <second_revision_name> percent: 50 tag: v2 ... When you are ready to route all traffic to the new version of the app, update the service again to send 100% of traffic to the second revision: Example of updated service spec sending all traffic to the second revision ... spec: traffic: - revisionName: <first_revision_name> percent: 0 - revisionName: <second_revision_name> percent: 100 tag: v2 ... Tip You can remove the first revision instead of setting it to 0% of traffic if you do not plan to roll back the revision. Non-routeable revision objects are then garbage-collected. Visit the URL of the first revision to verify that no more traffic is being sent to the old version of the app. 5.4. Routing Knative leverages OpenShift Container Platform TLS termination to provide routing for Knative services. When a Knative service is created, a OpenShift Container Platform route is automatically created for the service. This route is managed by the OpenShift Serverless Operator. The OpenShift Container Platform route exposes the Knative service through the same domain as the OpenShift Container Platform cluster. You can disable Operator control of OpenShift Container Platform routing so that you can configure a Knative route to directly use your TLS certificates instead. Knative routes can also be used alongside the OpenShift Container Platform route to provide additional fine-grained routing capabilities, such as traffic splitting. 5.4.1. Customizing labels and annotations for OpenShift Container Platform routes OpenShift Container Platform routes support the use of custom labels and annotations, which you can configure by modifying the metadata spec of a Knative service. Custom labels and annotations are propagated from the service to the Knative route, then to the Knative ingress, and finally to the OpenShift Container Platform route. Prerequisites You must have the OpenShift Serverless Operator and Knative Serving installed on your OpenShift Container Platform cluster. Install the OpenShift CLI ( oc ). Procedure Create a Knative service that contains the label or annotation that you want to propagate to the OpenShift Container Platform route: To create a service by using YAML: Example service created by using YAML apiVersion: serving.knative.dev/v1 kind: Service metadata: name: <service_name> labels: <label_name>: <label_value> annotations: <annotation_name>: <annotation_value> ... To create a service by using the Knative ( kn ) CLI, enter: Example service created by using a kn command USD kn service create <service_name> \ --image=<image> \ --annotation <annotation_name>=<annotation_value> \ --label <label_value>=<label_value> Verify that the OpenShift Container Platform route has been created with the annotation or label that you added by inspecting the output from the following command: Example command for verification USD oc get routes.route.openshift.io \ -l serving.knative.openshift.io/ingressName=<service_name> \ 1 -l serving.knative.openshift.io/ingressNamespace=<service_namespace> \ 2 -n knative-serving-ingress -o yaml \ | grep -e "<label_name>: \"<label_value>\"" -e "<annotation_name>: <annotation_value>" 3 1 Use the name of your service. 2 Use the namespace where your service was created. 3 Use your values for the label and annotation names and values. 5.4.2. Configuring OpenShift Container Platform routes for Knative services If you want to configure a Knative service to use your TLS certificate on OpenShift Container Platform, you must disable the automatic creation of a route for the service by the OpenShift Serverless Operator and instead manually create a route for the service. Note When you complete the following procedure, the default OpenShift Container Platform route in the knative-serving-ingress namespace is not created. However, the Knative route for the application is still created in this namespace. Prerequisites The OpenShift Serverless Operator and Knative Serving component must be installed on your OpenShift Container Platform cluster. Install the OpenShift CLI ( oc ). Procedure Create a Knative service that includes the serving.knative.openshift.io/disableRoute=true annotation: Important The serving.knative.openshift.io/disableRoute=true annotation instructs OpenShift Serverless to not automatically create a route for you. However, the service still shows a URL and reaches a status of Ready . This URL does not work externally until you create your own route with the same hostname as the hostname in the URL. Create a Knative Service resource: Example resource apiVersion: serving.knative.dev/v1 kind: Service metadata: name: <service_name> annotations: serving.knative.openshift.io/disableRoute: "true" spec: template: spec: containers: - image: <image> ... Apply the Service resource: USD oc apply -f <filename> Optional. Create a Knative service by using the kn service create command: Example kn command USD kn service create <service_name> \ --image=gcr.io/knative-samples/helloworld-go \ --annotation serving.knative.openshift.io/disableRoute=true Verify that no OpenShift Container Platform route has been created for the service: Example command USD USD oc get routes.route.openshift.io \ -l serving.knative.openshift.io/ingressName=USDKSERVICE_NAME \ -l serving.knative.openshift.io/ingressNamespace=USDKSERVICE_NAMESPACE \ -n knative-serving-ingress You will see the following output: No resources found in knative-serving-ingress namespace. Create a Route resource in the knative-serving-ingress namespace: apiVersion: route.openshift.io/v1 kind: Route metadata: annotations: haproxy.router.openshift.io/timeout: 600s 1 name: <route_name> 2 namespace: knative-serving-ingress 3 spec: host: <service_host> 4 port: targetPort: http2 to: kind: Service name: kourier weight: 100 tls: insecureEdgeTerminationPolicy: Allow termination: edge 5 key: |- -----BEGIN PRIVATE KEY----- [...] -----END PRIVATE KEY----- certificate: |- -----BEGIN CERTIFICATE----- [...] -----END CERTIFICATE----- caCertificate: |- -----BEGIN CERTIFICATE----- [...] -----END CERTIFICATE---- wildcardPolicy: None 1 The timeout value for the OpenShift Container Platform route. You must set the same value as the max-revision-timeout-seconds setting ( 600s by default). 2 The name of the OpenShift Container Platform route. 3 The namespace for the OpenShift Container Platform route. This must be knative-serving-ingress . 4 The hostname for external access. You can set this to <service_name>-<service_namespace>.<domain> . 5 The certificates you want to use. Currently, only edge termination is supported. Apply the Route resource: USD oc apply -f <filename> 5.4.3. Setting cluster availability to cluster local By default, Knative services are published to a public IP address. Being published to a public IP address means that Knative services are public applications, and have a publicly accessible URL. Publicly accessible URLs are accessible from outside of the cluster. However, developers may need to build back-end services that are only be accessible from inside the cluster, known as private services . Developers can label individual services in the cluster with the networking.knative.dev/visibility=cluster-local label to make them private. Important For OpenShift Serverless 1.15.0 and newer versions, the serving.knative.dev/visibility label is no longer available. You must update existing services to use the networking.knative.dev/visibility label instead. Prerequisites The OpenShift Serverless Operator and Knative Serving are installed on the cluster. You have created a Knative service. Procedure Set the visibility for your service by adding the networking.knative.dev/visibility=cluster-local label: USD oc label ksvc <service_name> networking.knative.dev/visibility=cluster-local Verification Check that the URL for your service is now in the format http://<service_name>.<namespace>.svc.cluster.local , by entering the following command and reviewing the output: USD oc get ksvc Example output NAME URL LATESTCREATED LATESTREADY READY REASON hello http://hello.default.svc.cluster.local hello-tx2g7 hello-tx2g7 True 5.4.4. Additional resources Route-specific annotations 5.5. Event sinks When you create an event source, you can specify a sink where events are sent to from the source. A sink is an addressable or a callable resource that can receive incoming events from other resources. Knative services, channels and brokers are all examples of sinks. Addressable objects receive and acknowledge an event delivered over HTTP to an address defined in their status.address.url field. As a special case, the core Kubernetes Service object also fulfills the addressable interface. Callable objects are able to receive an event delivered over HTTP and transform the event, returning 0 or 1 new events in the HTTP response. These returned events may be further processed in the same way that events from an external event source are processed. 5.5.1. Knative CLI sink flag When you create an event source by using the Knative ( kn ) CLI, you can specify a sink where events are sent to from that resource by using the --sink flag. The sink can be any addressable or callable resource that can receive incoming events from other resources. The following example creates a sink binding that uses a service, http://event-display.svc.cluster.local , as the sink: Example command using the sink flag USD kn source binding create bind-heartbeat \ --namespace sinkbinding-example \ --subject "Job:batch/v1:app=heartbeat-cron" \ --sink http://event-display.svc.cluster.local \ 1 --ce-override "sink=bound" 1 svc in http://event-display.svc.cluster.local determines that the sink is a Knative service. Other default sink prefixes include channel , and broker . Tip You can configure which CRs can be used with the --sink flag for Knative ( kn ) CLI commands by Customizing kn . 5.5.2. Connect an event source to a sink using the Developer perspective When you create an event source by using the OpenShift Container Platform web console, you can specify a sink where events are sent to from that resource. The sink can be any addressable or callable resource that can receive incoming events from other resources. Prerequisites The OpenShift Serverless Operator, Knative Serving, and Knative Eventing are installed on your OpenShift Container Platform cluster. You have logged in to the web console and are in the Developer perspective. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. You have created a sink, such as a Knative service, channel or broker. Procedure Create an event source of any type, by navigating to +Add Event Sources and then selecting the event source type that you want to create. In the Sink section of the Create Event Source form view, select your sink in the Resource list. Click Create . Verification You can verify that the event source was created and is connected to the sink by viewing the Topology page. In the Developer perspective, navigate to Topology . View the event source and click on the connected sink to see the sink details in the side panel. 5.5.3. Connecting a trigger to a sink You can connect a trigger to a sink, so that events from a broker are filtered before they are sent to the sink. A sink that is connected to a trigger is configured as a subscriber in the Trigger object's resource spec. Example of a Trigger object connected to a Kafka sink apiVersion: eventing.knative.dev/v1 kind: Trigger metadata: name: <trigger_name> 1 spec: ... subscriber: ref: apiVersion: eventing.knative.dev/v1alpha1 kind: KafkaSink name: <kafka_sink_name> 2 1 The name of the trigger being connected to the sink. 2 The name of a KafkaSink object. 5.6. Event delivery You can configure event delivery parameters that are applied in cases where an event fails to be delivered to an event sink. Configuring event delivery parameters, including a dead letter sink, ensures that any events that fail to be delivered to an event sink are retried. Otherwise, undelivered events are dropped. 5.6.1. Event delivery behavior patterns for channels and brokers Different channel and broker types have their own behavior patterns that are followed for event delivery. 5.6.1.1. Knative Kafka channels and brokers If an event is successfully delivered to a Kafka channel or broker receiver, the receiver responds with a 202 status code, which means that the event has been safely stored inside a Kafka topic and is not lost. If the receiver responds with any other status code, the event is not safely stored, and steps must be taken by the user to resolve the issue. 5.6.2. Configurable event delivery parameters The following parameters can be configured for event delivery: Dead letter sink You can configure the deadLetterSink delivery parameter so that if an event fails to be delivered, it is stored in the specified event sink. Undelivered events that are not stored in a dead letter sink are dropped. The dead letter sink be any addressable object that conforms to the Knative Eventing sink contract, such as a Knative service, a Kubernetes service, or a URI. Retries You can set a minimum number of times that the delivery must be retried before the event is sent to the dead letter sink, by configuring the retry delivery parameter with an integer value. Back off delay You can set the backoffDelay delivery parameter to specify the time delay before an event delivery retry is attempted after a failure. The duration of the backoffDelay parameter is specified using the ISO 8601 format. For example, PT1S specifies a 1 second delay. Back off policy The backoffPolicy delivery parameter can be used to specify the retry back off policy. The policy can be specified as either linear or exponential . When using the linear back off policy, the back off delay is equal to backoffDelay * <numberOfRetries> . When using the exponential backoff policy, the back off delay is equal to backoffDelay*2^<numberOfRetries> . 5.6.3. Examples of configuring event delivery parameters You can configure event delivery parameters for Broker , Trigger , Channel , and Subscription objects. If you configure event delivery parameters for a broker or channel, these parameters are propagated to triggers or subscriptions created for those objects. You can also set event delivery parameters for triggers or subscriptions to override the settings for the broker or channel. Example Broker object apiVersion: eventing.knative.dev/v1 kind: Broker metadata: ... spec: delivery: deadLetterSink: ref: apiVersion: eventing.knative.dev/v1alpha1 kind: KafkaSink name: <sink_name> backoffDelay: <duration> backoffPolicy: <policy_type> retry: <integer> ... Example Trigger object apiVersion: eventing.knative.dev/v1 kind: Trigger metadata: ... spec: broker: <broker_name> delivery: deadLetterSink: ref: apiVersion: serving.knative.dev/v1 kind: Service name: <sink_name> backoffDelay: <duration> backoffPolicy: <policy_type> retry: <integer> ... Example Channel object apiVersion: messaging.knative.dev/v1 kind: Channel metadata: ... spec: delivery: deadLetterSink: ref: apiVersion: serving.knative.dev/v1 kind: Service name: <sink_name> backoffDelay: <duration> backoffPolicy: <policy_type> retry: <integer> ... Example Subscription object apiVersion: messaging.knative.dev/v1 kind: Subscription metadata: ... spec: channel: apiVersion: messaging.knative.dev/v1 kind: Channel name: <channel_name> delivery: deadLetterSink: ref: apiVersion: serving.knative.dev/v1 kind: Service name: <sink_name> backoffDelay: <duration> backoffPolicy: <policy_type> retry: <integer> ... 5.6.4. Configuring event delivery ordering for triggers If you are using a Kafka broker, you can configure the delivery order of events from triggers to event sinks. Prerequisites The OpenShift Serverless Operator, Knative Eventing, and Knative Kafka are installed on your OpenShift Container Platform cluster. Kafka broker is enabled for use on your cluster, and you have created a Kafka broker. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. You have installed the OpenShift ( oc ) CLI. Procedure Create or modify a Trigger object and set the kafka.eventing.knative.dev/delivery.order annotation: apiVersion: eventing.knative.dev/v1 kind: Trigger metadata: name: <trigger_name> annotations: kafka.eventing.knative.dev/delivery.order: ordered ... The supported consumer delivery guarantees are: unordered An unordered consumer is a non-blocking consumer that delivers messages unordered, while preserving proper offset management. ordered An ordered consumer is a per-partition blocking consumer that waits for a successful response from the CloudEvent subscriber before it delivers the message of the partition. The default ordering guarantee is unordered . Apply the Trigger object: USD oc apply -f <filename> 5.7. Listing event sources and event source types It is possible to view a list of all event sources or event source types that exist or are available for use on your OpenShift Container Platform cluster. You can use the Knative ( kn ) CLI or the Developer perspective in the OpenShift Container Platform web console to list available event sources or event source types. 5.7.1. Listing available event source types by using the Knative CLI Using the Knative ( kn ) CLI provides a streamlined and intuitive user interface to view available event source types on your cluster. You can list event source types that can be created and used on your cluster by using the kn source list-types CLI command. Prerequisites The OpenShift Serverless Operator and Knative Eventing are installed on the cluster. You have installed the Knative ( kn ) CLI. Procedure List the available event source types in the terminal: USD kn source list-types Example output TYPE NAME DESCRIPTION ApiServerSource apiserversources.sources.knative.dev Watch and send Kubernetes API events to a sink PingSource pingsources.sources.knative.dev Periodically send ping events to a sink SinkBinding sinkbindings.sources.knative.dev Binding for connecting a PodSpecable to a sink Optional: You can also list the available event source types in YAML format: USD kn source list-types -o yaml 5.7.2. Viewing available event source types within the Developer perspective It is possible to view a list of all available event source types on your cluster. Using the OpenShift Container Platform web console provides a streamlined and intuitive user interface to view available event source types. Prerequisites You have logged in to the OpenShift Container Platform web console. The OpenShift Serverless Operator and Knative Eventing are installed on your OpenShift Container Platform cluster. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. Procedure Access the Developer perspective. Click +Add . Click Event source . View the available event source types. 5.7.3. Listing available event sources by using the Knative CLI Using the Knative ( kn ) CLI provides a streamlined and intuitive user interface to view existing event sources on your cluster. You can list existing event sources by using the kn source list command. Prerequisites The OpenShift Serverless Operator and Knative Eventing are installed on the cluster. You have installed the Knative ( kn ) CLI. Procedure List the existing event sources in the terminal: USD kn source list Example output NAME TYPE RESOURCE SINK READY a1 ApiServerSource apiserversources.sources.knative.dev ksvc:eshow2 True b1 SinkBinding sinkbindings.sources.knative.dev ksvc:eshow3 False p1 PingSource pingsources.sources.knative.dev ksvc:eshow1 True Optional: You can list event sources of a specific type only, by using the --type flag: USD kn source list --type <event_source_type> Example command USD kn source list --type PingSource Example output NAME TYPE RESOURCE SINK READY p1 PingSource pingsources.sources.knative.dev ksvc:eshow1 True 5.8. Creating an API server source The API server source is an event source that can be used to connect an event sink, such as a Knative service, to the Kubernetes API server. The API server source watches for Kubernetes events and forwards them to the Knative Eventing broker. 5.8.1. Creating an API server source by using the web console After Knative Eventing is installed on your cluster, you can create an API server source by using the web console. Using the OpenShift Container Platform web console provides a streamlined and intuitive user interface to create an event source. Prerequisites You have logged in to the OpenShift Container Platform web console. The OpenShift Serverless Operator and Knative Eventing are installed on the cluster. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. You have installed the OpenShift CLI ( oc ). Procedure If you want to re-use an existing service account, you can modify your existing ServiceAccount resource to include the required permissions instead of creating a new resource. Create a service account, role, and role binding for the event source as a YAML file: apiVersion: v1 kind: ServiceAccount metadata: name: events-sa namespace: default 1 --- apiVersion: rbac.authorization.k8s.io/v1 kind: Role metadata: name: event-watcher namespace: default 2 rules: - apiGroups: - "" resources: - events verbs: - get - list - watch --- apiVersion: rbac.authorization.k8s.io/v1 kind: RoleBinding metadata: name: k8s-ra-event-watcher namespace: default 3 roleRef: apiGroup: rbac.authorization.k8s.io kind: Role name: event-watcher subjects: - kind: ServiceAccount name: events-sa namespace: default 4 1 2 3 4 Change this namespace to the namespace that you have selected for installing the event source. Apply the YAML file: USD oc apply -f <filename> In the Developer perspective, navigate to +Add Event Source . The Event Sources page is displayed. Optional: If you have multiple providers for your event sources, select the required provider from the Providers list to filter the available event sources from the provider. Select ApiServerSource and then click Create Event Source . The Create Event Source page is displayed. Configure the ApiServerSource settings by using the Form view or YAML view : Note You can switch between the Form view and YAML view . The data is persisted when switching between the views. Enter v1 as the APIVERSION and Event as the KIND . Select the Service Account Name for the service account that you created. Select the Sink for the event source. A Sink can be either a Resource , such as a channel, broker, or service, or a URI . Click Create . Verification After you have created the API server source, you will see it connected to the service it is sinked to in the Topology view. Note If a URI sink is used, modify the URI by right-clicking on URI sink Edit URI . Deleting the API server source Navigate to the Topology view. Right-click the API server source and select Delete ApiServerSource . 5.8.2. Creating an API server source by using the Knative CLI You can use the kn source apiserver create command to create an API server source by using the kn CLI. Using the kn CLI to create an API server source provides a more streamlined and intuitive user interface than modifying YAML files directly. Prerequisites The OpenShift Serverless Operator and Knative Eventing are installed on the cluster. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. You have installed the OpenShift CLI ( oc ). You have installed the Knative ( kn ) CLI. Procedure If you want to re-use an existing service account, you can modify your existing ServiceAccount resource to include the required permissions instead of creating a new resource. Create a service account, role, and role binding for the event source as a YAML file: apiVersion: v1 kind: ServiceAccount metadata: name: events-sa namespace: default 1 --- apiVersion: rbac.authorization.k8s.io/v1 kind: Role metadata: name: event-watcher namespace: default 2 rules: - apiGroups: - "" resources: - events verbs: - get - list - watch --- apiVersion: rbac.authorization.k8s.io/v1 kind: RoleBinding metadata: name: k8s-ra-event-watcher namespace: default 3 roleRef: apiGroup: rbac.authorization.k8s.io kind: Role name: event-watcher subjects: - kind: ServiceAccount name: events-sa namespace: default 4 1 2 3 4 Change this namespace to the namespace that you have selected for installing the event source. Apply the YAML file: USD oc apply -f <filename> Create an API server source that has an event sink. In the following example, the sink is a broker: USD kn source apiserver create <event_source_name> --sink broker:<broker_name> --resource "event:v1" --service-account <service_account_name> --mode Resource To check that the API server source is set up correctly, create a Knative service that dumps incoming messages to its log: USD kn service create <service_name> --image quay.io/openshift-knative/knative-eventing-sources-event-display:latest If you used a broker as an event sink, create a trigger to filter events from the default broker to the service: USD kn trigger create <trigger_name> --sink ksvc:<service_name> Create events by launching a pod in the default namespace: USD oc create deployment hello-node --image quay.io/openshift-knative/knative-eventing-sources-event-display:latest Check that the controller is mapped correctly by inspecting the output generated by the following command: USD kn source apiserver describe <source_name> Example output Name: mysource Namespace: default Annotations: sources.knative.dev/creator=developer, sources.knative.dev/lastModifier=developer Age: 3m ServiceAccountName: events-sa Mode: Resource Sink: Name: default Namespace: default Kind: Broker (eventing.knative.dev/v1) Resources: Kind: event (v1) Controller: false Conditions: OK TYPE AGE REASON ++ Ready 3m ++ Deployed 3m ++ SinkProvided 3m ++ SufficientPermissions 3m ++ EventTypesProvided 3m Verification You can verify that the Kubernetes events were sent to Knative by looking at the message dumper function logs. Get the pods: USD oc get pods View the message dumper function logs for the pods: USD oc logs USD(oc get pod -o name | grep event-display) -c user-container Example output ☁\ufe0f cloudevents.Event Validation: valid Context Attributes, specversion: 1.0 type: dev.knative.apiserver.resource.update datacontenttype: application/json ... Data, { "apiVersion": "v1", "involvedObject": { "apiVersion": "v1", "fieldPath": "spec.containers{hello-node}", "kind": "Pod", "name": "hello-node", "namespace": "default", ..... }, "kind": "Event", "message": "Started container", "metadata": { "name": "hello-node.159d7608e3a3572c", "namespace": "default", .... }, "reason": "Started", ... } Deleting the API server source Delete the trigger: USD kn trigger delete <trigger_name> Delete the event source: USD kn source apiserver delete <source_name> Delete the service account, cluster role, and cluster binding: USD oc delete -f authentication.yaml 5.8.2.1. Knative CLI sink flag When you create an event source by using the Knative ( kn ) CLI, you can specify a sink where events are sent to from that resource by using the --sink flag. The sink can be any addressable or callable resource that can receive incoming events from other resources. The following example creates a sink binding that uses a service, http://event-display.svc.cluster.local , as the sink: Example command using the sink flag USD kn source binding create bind-heartbeat \ --namespace sinkbinding-example \ --subject "Job:batch/v1:app=heartbeat-cron" \ --sink http://event-display.svc.cluster.local \ 1 --ce-override "sink=bound" 1 svc in http://event-display.svc.cluster.local determines that the sink is a Knative service. Other default sink prefixes include channel , and broker . 5.8.3. Creating an API server source by using YAML files Creating Knative resources by using YAML files uses a declarative API, which enables you to describe event sources declaratively and in a reproducible manner. To create an API server source by using YAML, you must create a YAML file that defines an ApiServerSource object, then apply it by using the oc apply command. Prerequisites The OpenShift Serverless Operator and Knative Eventing are installed on the cluster. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. You have created the default broker in the same namespace as the one defined in the API server source YAML file. Install the OpenShift CLI ( oc ). Procedure If you want to re-use an existing service account, you can modify your existing ServiceAccount resource to include the required permissions instead of creating a new resource. Create a service account, role, and role binding for the event source as a YAML file: apiVersion: v1 kind: ServiceAccount metadata: name: events-sa namespace: default 1 --- apiVersion: rbac.authorization.k8s.io/v1 kind: Role metadata: name: event-watcher namespace: default 2 rules: - apiGroups: - "" resources: - events verbs: - get - list - watch --- apiVersion: rbac.authorization.k8s.io/v1 kind: RoleBinding metadata: name: k8s-ra-event-watcher namespace: default 3 roleRef: apiGroup: rbac.authorization.k8s.io kind: Role name: event-watcher subjects: - kind: ServiceAccount name: events-sa namespace: default 4 1 2 3 4 Change this namespace to the namespace that you have selected for installing the event source. Apply the YAML file: USD oc apply -f <filename> Create an API server source as a YAML file: apiVersion: sources.knative.dev/v1alpha1 kind: ApiServerSource metadata: name: testevents spec: serviceAccountName: events-sa mode: Resource resources: - apiVersion: v1 kind: Event sink: ref: apiVersion: eventing.knative.dev/v1 kind: Broker name: default Apply the ApiServerSource YAML file: USD oc apply -f <filename> To check that the API server source is set up correctly, create a Knative service as a YAML file that dumps incoming messages to its log: apiVersion: serving.knative.dev/v1 kind: Service metadata: name: event-display namespace: default spec: template: spec: containers: - image: quay.io/openshift-knative/knative-eventing-sources-event-display:latest Apply the Service YAML file: USD oc apply -f <filename> Create a Trigger object as a YAML file that filters events from the default broker to the service created in the step: apiVersion: eventing.knative.dev/v1 kind: Trigger metadata: name: event-display-trigger namespace: default spec: broker: default subscriber: ref: apiVersion: serving.knative.dev/v1 kind: Service name: event-display Apply the Trigger YAML file: USD oc apply -f <filename> Create events by launching a pod in the default namespace: USD oc create deployment hello-node --image=quay.io/openshift-knative/knative-eventing-sources-event-display Check that the controller is mapped correctly, by entering the following command and inspecting the output: USD oc get apiserversource.sources.knative.dev testevents -o yaml Example output apiVersion: sources.knative.dev/v1alpha1 kind: ApiServerSource metadata: annotations: creationTimestamp: "2020-04-07T17:24:54Z" generation: 1 name: testevents namespace: default resourceVersion: "62868" selfLink: /apis/sources.knative.dev/v1alpha1/namespaces/default/apiserversources/testevents2 uid: 1603d863-bb06-4d1c-b371-f580b4db99fa spec: mode: Resource resources: - apiVersion: v1 controller: false controllerSelector: apiVersion: "" kind: "" name: "" uid: "" kind: Event labelSelector: {} serviceAccountName: events-sa sink: ref: apiVersion: eventing.knative.dev/v1 kind: Broker name: default Verification To verify that the Kubernetes events were sent to Knative, you can look at the message dumper function logs. Get the pods by entering the following command: USD oc get pods View the message dumper function logs for the pods by entering the following command: USD oc logs USD(oc get pod -o name | grep event-display) -c user-container Example output ☁\ufe0f cloudevents.Event Validation: valid Context Attributes, specversion: 1.0 type: dev.knative.apiserver.resource.update datacontenttype: application/json ... Data, { "apiVersion": "v1", "involvedObject": { "apiVersion": "v1", "fieldPath": "spec.containers{hello-node}", "kind": "Pod", "name": "hello-node", "namespace": "default", ..... }, "kind": "Event", "message": "Started container", "metadata": { "name": "hello-node.159d7608e3a3572c", "namespace": "default", .... }, "reason": "Started", ... } Deleting the API server source Delete the trigger: USD oc delete -f trigger.yaml Delete the event source: USD oc delete -f k8s-events.yaml Delete the service account, cluster role, and cluster binding: USD oc delete -f authentication.yaml 5.9. Creating a ping source A ping source is an event source that can be used to periodically send ping events with a constant payload to an event consumer. A ping source can be used to schedule sending events, similar to a timer. 5.9.1. Creating a ping source by using the web console After Knative Eventing is installed on your cluster, you can create a ping source by using the web console. Using the OpenShift Container Platform web console provides a streamlined and intuitive user interface to create an event source. Prerequisites You have logged in to the OpenShift Container Platform web console. The OpenShift Serverless Operator, Knative Serving and Knative Eventing are installed on the cluster. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. Procedure To verify that the ping source is working, create a simple Knative service that dumps incoming messages to the logs of the service. In the Developer perspective, navigate to +Add YAML . Copy the example YAML: apiVersion: serving.knative.dev/v1 kind: Service metadata: name: event-display spec: template: spec: containers: - image: quay.io/openshift-knative/knative-eventing-sources-event-display:latest Click Create . Create a ping source in the same namespace as the service created in the step, or any other sink that you want to send events to. In the Developer perspective, navigate to +Add Event Source . The Event Sources page is displayed. Optional: If you have multiple providers for your event sources, select the required provider from the Providers list to filter the available event sources from the provider. Select Ping Source and then click Create Event Source . The Create Event Source page is displayed. Note You can configure the PingSource settings by using the Form view or YAML view and can switch between the views. The data is persisted when switching between the views. Enter a value for Schedule . In this example, the value is */2 * * * * , which creates a PingSource that sends a message every two minutes. Optional: You can enter a value for Data , which is the message payload. Select a Sink . This can be either a Resource or a URI . In this example, the event-display service created in the step is used as the Resource sink. Click Create . Verification You can verify that the ping source was created and is connected to the sink by viewing the Topology page. In the Developer perspective, navigate to Topology . View the ping source and sink. Deleting the ping source Navigate to the Topology view. Right-click the API server source and select Delete Ping Source . 5.9.2. Creating a ping source by using the Knative CLI You can use the kn source ping create command to create a ping source by using the Knative ( kn ) CLI. Using the Knative CLI to create event sources provides a more streamlined and intuitive user interface than modifying YAML files directly. Prerequisites The OpenShift Serverless Operator, Knative Serving and Knative Eventing are installed on the cluster. You have installed the Knative ( kn ) CLI. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. Optional: If you want to use the verification steps for this procedure, install the OpenShift CLI ( oc ). Procedure To verify that the ping source is working, create a simple Knative service that dumps incoming messages to the service logs: USD kn service create event-display \ --image quay.io/openshift-knative/knative-eventing-sources-event-display:latest For each set of ping events that you want to request, create a ping source in the same namespace as the event consumer: USD kn source ping create test-ping-source \ --schedule "*/2 * * * *" \ --data '{"message": "Hello world!"}' \ --sink ksvc:event-display Check that the controller is mapped correctly by entering the following command and inspecting the output: USD kn source ping describe test-ping-source Example output Name: test-ping-source Namespace: default Annotations: sources.knative.dev/creator=developer, sources.knative.dev/lastModifier=developer Age: 15s Schedule: */2 * * * * Data: {"message": "Hello world!"} Sink: Name: event-display Namespace: default Resource: Service (serving.knative.dev/v1) Conditions: OK TYPE AGE REASON ++ Ready 8s ++ Deployed 8s ++ SinkProvided 15s ++ ValidSchedule 15s ++ EventTypeProvided 15s ++ ResourcesCorrect 15s Verification You can verify that the Kubernetes events were sent to the Knative event sink by looking at the logs of the sink pod. By default, Knative services terminate their pods if no traffic is received within a 60 second period. The example shown in this guide creates a ping source that sends a message every 2 minutes, so each message should be observed in a newly created pod. Watch for new pods created: USD watch oc get pods Cancel watching the pods using Ctrl+C, then look at the logs of the created pod: USD oc logs USD(oc get pod -o name | grep event-display) -c user-container Example output ☁\ufe0f cloudevents.Event Validation: valid Context Attributes, specversion: 1.0 type: dev.knative.sources.ping source: /apis/v1/namespaces/default/pingsources/test-ping-source id: 99e4f4f6-08ff-4bff-acf1-47f61ded68c9 time: 2020-04-07T16:16:00.000601161Z datacontenttype: application/json Data, { "message": "Hello world!" } Deleting the ping source Delete the ping source: USD kn delete pingsources.sources.knative.dev <ping_source_name> 5.9.2.1. Knative CLI sink flag When you create an event source by using the Knative ( kn ) CLI, you can specify a sink where events are sent to from that resource by using the --sink flag. The sink can be any addressable or callable resource that can receive incoming events from other resources. The following example creates a sink binding that uses a service, http://event-display.svc.cluster.local , as the sink: Example command using the sink flag USD kn source binding create bind-heartbeat \ --namespace sinkbinding-example \ --subject "Job:batch/v1:app=heartbeat-cron" \ --sink http://event-display.svc.cluster.local \ 1 --ce-override "sink=bound" 1 svc in http://event-display.svc.cluster.local determines that the sink is a Knative service. Other default sink prefixes include channel , and broker . 5.9.3. Creating a ping source by using YAML Creating Knative resources by using YAML files uses a declarative API, which enables you to describe event sources declaratively and in a reproducible manner. To create a serverless ping source by using YAML, you must create a YAML file that defines a PingSource object, then apply it by using oc apply . Example PingSource object apiVersion: sources.knative.dev/v1 kind: PingSource metadata: name: test-ping-source spec: schedule: "*/2 * * * *" 1 data: '{"message": "Hello world!"}' 2 sink: 3 ref: apiVersion: serving.knative.dev/v1 kind: Service name: event-display 1 The schedule of the event specified using CRON expression . 2 The event message body expressed as a JSON encoded data string. 3 These are the details of the event consumer. In this example, we are using a Knative service named event-display . Prerequisites The OpenShift Serverless Operator, Knative Serving and Knative Eventing are installed on the cluster. Install the OpenShift CLI ( oc ). You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. Procedure To verify that the ping source is working, create a simple Knative service that dumps incoming messages to the service's logs. Create a service YAML file: apiVersion: serving.knative.dev/v1 kind: Service metadata: name: event-display spec: template: spec: containers: - image: quay.io/openshift-knative/knative-eventing-sources-event-display:latest Create the service: USD oc apply -f <filename> For each set of ping events that you want to request, create a ping source in the same namespace as the event consumer. Create a YAML file for the ping source: apiVersion: sources.knative.dev/v1 kind: PingSource metadata: name: test-ping-source spec: schedule: "*/2 * * * *" data: '{"message": "Hello world!"}' sink: ref: apiVersion: serving.knative.dev/v1 kind: Service name: event-display Create the ping source: USD oc apply -f <filename> Check that the controller is mapped correctly by entering the following command: USD oc get pingsource.sources.knative.dev <ping_source_name> -oyaml Example output apiVersion: sources.knative.dev/v1 kind: PingSource metadata: annotations: sources.knative.dev/creator: developer sources.knative.dev/lastModifier: developer creationTimestamp: "2020-04-07T16:11:14Z" generation: 1 name: test-ping-source namespace: default resourceVersion: "55257" selfLink: /apis/sources.knative.dev/v1/namespaces/default/pingsources/test-ping-source uid: 3d80d50b-f8c7-4c1b-99f7-3ec00e0a8164 spec: data: '{ value: "hello" }' schedule: '*/2 * * * *' sink: ref: apiVersion: serving.knative.dev/v1 kind: Service name: event-display namespace: default Verification You can verify that the Kubernetes events were sent to the Knative event sink by looking at the sink pod's logs. By default, Knative services terminate their pods if no traffic is received within a 60 second period. The example shown in this guide creates a PingSource that sends a message every 2 minutes, so each message should be observed in a newly created pod. Watch for new pods created: USD watch oc get pods Cancel watching the pods using Ctrl+C, then look at the logs of the created pod: USD oc logs USD(oc get pod -o name | grep event-display) -c user-container Example output ☁\ufe0f cloudevents.Event Validation: valid Context Attributes, specversion: 1.0 type: dev.knative.sources.ping source: /apis/v1/namespaces/default/pingsources/test-ping-source id: 042ff529-240e-45ee-b40c-3a908129853e time: 2020-04-07T16:22:00.000791674Z datacontenttype: application/json Data, { "message": "Hello world!" } Deleting the ping source Delete the ping source: USD oc delete -f <filename> Example command USD oc delete -f ping-source.yaml 5.10. Custom event sources If you need to ingress events from an event producer that is not included in Knative, or from a producer that emits events which are not in the CloudEvent format, you can do this by creating a custom event source. You can create a custom event source by using one of the following methods: Use a PodSpecable object as an event source, by creating a sink binding. Use a container as an event source, by creating a container source. 5.10.1. Sink binding The SinkBinding object supports decoupling event production from delivery addressing. Sink binding is used to connect event producers to an event consumer, or sink . An event producer is a Kubernetes resource that embeds a PodSpec template and produces events. A sink is an addressable Kubernetes object that can receive events. The SinkBinding object injects environment variables into the PodTemplateSpec of the sink, which means that the application code does not need to interact directly with the Kubernetes API to locate the event destination. These environment variables are as follows: K_SINK The URL of the resolved sink. K_CE_OVERRIDES A JSON object that specifies overrides to the outbound event. 5.10.1.1. Creating a sink binding by using YAML Creating Knative resources by using YAML files uses a declarative API, which enables you to describe event sources declaratively and in a reproducible manner. To create a sink binding by using YAML, you must create a YAML file that defines an SinkBinding object, then apply it by using the oc apply command. Prerequisites The OpenShift Serverless Operator, Knative Serving and Knative Eventing are installed on the cluster. Install the OpenShift CLI ( oc ). You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. Procedure To check that sink binding is set up correctly, create a Knative event display service, or event sink, that dumps incoming messages to its log. Create a service YAML file: Example service YAML file apiVersion: serving.knative.dev/v1 kind: Service metadata: name: event-display spec: template: spec: containers: - image: quay.io/openshift-knative/knative-eventing-sources-event-display:latest Create the service: USD oc apply -f <filename> Create a sink binding instance that directs events to the service. Create a sink binding YAML file: Example service YAML file apiVersion: sources.knative.dev/v1alpha1 kind: SinkBinding metadata: name: bind-heartbeat spec: subject: apiVersion: batch/v1 kind: Job 1 selector: matchLabels: app: heartbeat-cron sink: ref: apiVersion: serving.knative.dev/v1 kind: Service name: event-display 1 In this example, any Job with the label app: heartbeat-cron will be bound to the event sink. Create the sink binding: USD oc apply -f <filename> Create a CronJob object. Create a cron job YAML file: Example cron job YAML file apiVersion: batch/v1beta1 kind: CronJob metadata: name: heartbeat-cron spec: # Run every minute schedule: "* * * * *" jobTemplate: metadata: labels: app: heartbeat-cron bindings.knative.dev/include: "true" spec: template: spec: restartPolicy: Never containers: - name: single-heartbeat image: quay.io/openshift-knative/heartbeats:latest args: - --period=1 env: - name: ONE_SHOT value: "true" - name: POD_NAME valueFrom: fieldRef: fieldPath: metadata.name - name: POD_NAMESPACE valueFrom: fieldRef: fieldPath: metadata.namespace Important To use sink binding, you must manually add a bindings.knative.dev/include=true label to your Knative resources. For example, to add this label to a CronJob resource, add the following lines to the Job resource YAML definition: jobTemplate: metadata: labels: app: heartbeat-cron bindings.knative.dev/include: "true" Create the cron job: USD oc apply -f <filename> Check that the controller is mapped correctly by entering the following command and inspecting the output: USD oc get sinkbindings.sources.knative.dev bind-heartbeat -oyaml Example output spec: sink: ref: apiVersion: serving.knative.dev/v1 kind: Service name: event-display namespace: default subject: apiVersion: batch/v1 kind: Job namespace: default selector: matchLabels: app: heartbeat-cron Verification You can verify that the Kubernetes events were sent to the Knative event sink by looking at the message dumper function logs. Enter the command: USD oc get pods Enter the command: USD oc logs USD(oc get pod -o name | grep event-display) -c user-container Example output ☁\ufe0f cloudevents.Event Validation: valid Context Attributes, specversion: 1.0 type: dev.knative.eventing.samples.heartbeat source: https://knative.dev/eventing-contrib/cmd/heartbeats/#event-test/mypod id: 2b72d7bf-c38f-4a98-a433-608fbcdd2596 time: 2019-10-18T15:23:20.809775386Z contenttype: application/json Extensions, beats: true heart: yes the: 42 Data, { "id": 1, "label": "" } 5.10.1.2. Creating a sink binding by using the Knative CLI You can use the kn source binding create command to create a sink binding by using the Knative ( kn ) CLI. Using the Knative CLI to create event sources provides a more streamlined and intuitive user interface than modifying YAML files directly. Prerequisites The OpenShift Serverless Operator, Knative Serving and Knative Eventing are installed on the cluster. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. Install the Knative ( kn ) CLI. Install the OpenShift CLI ( oc ). Note The following procedure requires you to create YAML files. If you change the names of the YAML files from those used in the examples, you must ensure that you also update the corresponding CLI commands. Procedure To check that sink binding is set up correctly, create a Knative event display service, or event sink, that dumps incoming messages to its log: USD kn service create event-display --image quay.io/openshift-knative/knative-eventing-sources-event-display:latest Create a sink binding instance that directs events to the service: USD kn source binding create bind-heartbeat --subject Job:batch/v1:app=heartbeat-cron --sink ksvc:event-display Create a CronJob object. Create a cron job YAML file: Example cron job YAML file apiVersion: batch/v1beta1 kind: CronJob metadata: name: heartbeat-cron spec: # Run every minute schedule: "* * * * *" jobTemplate: metadata: labels: app: heartbeat-cron bindings.knative.dev/include: "true" spec: template: spec: restartPolicy: Never containers: - name: single-heartbeat image: quay.io/openshift-knative/heartbeats:latest args: - --period=1 env: - name: ONE_SHOT value: "true" - name: POD_NAME valueFrom: fieldRef: fieldPath: metadata.name - name: POD_NAMESPACE valueFrom: fieldRef: fieldPath: metadata.namespace Important To use sink binding, you must manually add a bindings.knative.dev/include=true label to your Knative CRs. For example, to add this label to a CronJob CR, add the following lines to the Job CR YAML definition: jobTemplate: metadata: labels: app: heartbeat-cron bindings.knative.dev/include: "true" Create the cron job: USD oc apply -f <filename> Check that the controller is mapped correctly by entering the following command and inspecting the output: USD kn source binding describe bind-heartbeat Example output Name: bind-heartbeat Namespace: demo-2 Annotations: sources.knative.dev/creator=minikube-user, sources.knative.dev/lastModifier=minikub ... Age: 2m Subject: Resource: job (batch/v1) Selector: app: heartbeat-cron Sink: Name: event-display Resource: Service (serving.knative.dev/v1) Conditions: OK TYPE AGE REASON ++ Ready 2m Verification You can verify that the Kubernetes events were sent to the Knative event sink by looking at the message dumper function logs. View the message dumper function logs by entering the following commands: USD oc get pods USD oc logs USD(oc get pod -o name | grep event-display) -c user-container Example output ☁\ufe0f cloudevents.Event Validation: valid Context Attributes, specversion: 1.0 type: dev.knative.eventing.samples.heartbeat source: https://knative.dev/eventing-contrib/cmd/heartbeats/#event-test/mypod id: 2b72d7bf-c38f-4a98-a433-608fbcdd2596 time: 2019-10-18T15:23:20.809775386Z contenttype: application/json Extensions, beats: true heart: yes the: 42 Data, { "id": 1, "label": "" } 5.10.1.2.1. Knative CLI sink flag When you create an event source by using the Knative ( kn ) CLI, you can specify a sink where events are sent to from that resource by using the --sink flag. The sink can be any addressable or callable resource that can receive incoming events from other resources. The following example creates a sink binding that uses a service, http://event-display.svc.cluster.local , as the sink: Example command using the sink flag USD kn source binding create bind-heartbeat \ --namespace sinkbinding-example \ --subject "Job:batch/v1:app=heartbeat-cron" \ --sink http://event-display.svc.cluster.local \ 1 --ce-override "sink=bound" 1 svc in http://event-display.svc.cluster.local determines that the sink is a Knative service. Other default sink prefixes include channel , and broker . 5.10.1.3. Creating a sink binding by using the web console After Knative Eventing is installed on your cluster, you can create a sink binding by using the web console. Using the OpenShift Container Platform web console provides a streamlined and intuitive user interface to create an event source. Prerequisites You have logged in to the OpenShift Container Platform web console. The OpenShift Serverless Operator, Knative Serving, and Knative Eventing are installed on your OpenShift Container Platform cluster. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. Procedure Create a Knative service to use as a sink: In the Developer perspective, navigate to +Add YAML . Copy the example YAML: apiVersion: serving.knative.dev/v1 kind: Service metadata: name: event-display spec: template: spec: containers: - image: quay.io/openshift-knative/knative-eventing-sources-event-display:latest Click Create . Create a CronJob resource that is used as an event source and sends an event every minute. In the Developer perspective, navigate to +Add YAML . Copy the example YAML: apiVersion: batch/v1 kind: CronJob metadata: name: heartbeat-cron spec: # Run every minute schedule: "*/1 * * * *" jobTemplate: metadata: labels: app: heartbeat-cron bindings.knative.dev/include: true 1 spec: template: spec: restartPolicy: Never containers: - name: single-heartbeat image: quay.io/openshift-knative/heartbeats args: - --period=1 env: - name: ONE_SHOT value: "true" - name: POD_NAME valueFrom: fieldRef: fieldPath: metadata.name - name: POD_NAMESPACE valueFrom: fieldRef: fieldPath: metadata.namespace 1 Ensure that you include the bindings.knative.dev/include: true label. The default namespace selection behavior of OpenShift Serverless uses inclusion mode. Click Create . Create a sink binding in the same namespace as the service created in the step, or any other sink that you want to send events to. In the Developer perspective, navigate to +Add Event Source . The Event Sources page is displayed. Optional: If you have multiple providers for your event sources, select the required provider from the Providers list to filter the available event sources from the provider. Select Sink Binding and then click Create Event Source . The Create Event Source page is displayed. Note You can configure the Sink Binding settings by using the Form view or YAML view and can switch between the views. The data is persisted when switching between the views. In the apiVersion field enter batch/v1 . In the Kind field enter Job . Note The CronJob kind is not supported directly by OpenShift Serverless sink binding, so the Kind field must target the Job objects created by the cron job, rather than the cron job object itself. Select a Sink . This can be either a Resource or a URI . In this example, the event-display service created in the step is used as the Resource sink. In the Match labels section: Enter app in the Name field. Enter heartbeat-cron in the Value field. Note The label selector is required when using cron jobs with sink binding, rather than the resource name. This is because jobs created by a cron job do not have a predictable name, and contain a randomly generated string in their name. For example, hearthbeat-cron-1cc23f . Click Create . Verification You can verify that the sink binding, sink, and cron job have been created and are working correctly by viewing the Topology page and pod logs. In the Developer perspective, navigate to Topology . View the sink binding, sink, and heartbeats cron job. Observe that successful jobs are being registered by the cron job once the sink binding is added. This means that the sink binding is successfully reconfiguring the jobs created by the cron job. Browse the logs of the event-display service pod to see events produced by the heartbeats cron job. 5.10.1.4. Sink binding reference You can use a PodSpecable object as an event source by creating a sink binding. You can configure multiple parameters when creating a SinkBinding object. SinkBinding objects support the following parameters: Field Description Required or optional apiVersion Specifies the API version, for example sources.knative.dev/v1 . Required kind Identifies this resource object as a SinkBinding object. Required metadata Specifies metadata that uniquely identifies the SinkBinding object. For example, a name . Required spec Specifies the configuration information for this SinkBinding object. Required spec.sink A reference to an object that resolves to a URI to use as the sink. Required spec.subject References the resources for which the runtime contract is augmented by binding implementations. Required spec.ceOverrides Defines overrides to control the output format and modifications to the event sent to the sink. Optional 5.10.1.4.1. Subject parameter The Subject parameter references the resources for which the runtime contract is augmented by binding implementations. You can configure multiple fields for a Subject definition. The Subject definition supports the following fields: Field Description Required or optional apiVersion API version of the referent. Required kind Kind of the referent. Required namespace Namespace of the referent. If omitted, this defaults to the namespace of the object. Optional name Name of the referent. Do not use if you configure selector . selector Selector of the referents. Do not use if you configure name . selector.matchExpressions A list of label selector requirements. Only use one of either matchExpressions or matchLabels . selector.matchExpressions.key The label key that the selector applies to. Required if using matchExpressions . selector.matchExpressions.operator Represents a key's relationship to a set of values. Valid operators are In , NotIn , Exists and DoesNotExist . Required if using matchExpressions . selector.matchExpressions.values An array of string values. If the operator parameter value is In or NotIn , the values array must be non-empty. If the operator parameter value is Exists or DoesNotExist , the values array must be empty. This array is replaced during a strategic merge patch. Required if using matchExpressions . selector.matchLabels A map of key-value pairs. Each key-value pair in the matchLabels map is equivalent to an element of matchExpressions , where the key field is matchLabels.<key> , the operator is In , and the values array contains only matchLabels.<value> . Only use one of either matchExpressions or matchLabels . Subject parameter examples Given the following YAML, the Deployment object named mysubject in the default namespace is selected: apiVersion: sources.knative.dev/v1 kind: SinkBinding metadata: name: bind-heartbeat spec: subject: apiVersion: apps/v1 kind: Deployment namespace: default name: mysubject ... Given the following YAML, any Job object with the label working=example in the default namespace is selected: apiVersion: sources.knative.dev/v1 kind: SinkBinding metadata: name: bind-heartbeat spec: subject: apiVersion: batch/v1 kind: Job namespace: default selector: matchLabels: working: example ... Given the following YAML, any Pod object with the label working=example or working=sample in the default namespace is selected: apiVersion: sources.knative.dev/v1 kind: SinkBinding metadata: name: bind-heartbeat spec: subject: apiVersion: v1 kind: Pod namespace: default selector: - matchExpression: key: working operator: In values: - example - sample ... 5.10.1.4.2. CloudEvent overrides A ceOverrides definition provides overrides that control the CloudEvent's output format and modifications sent to the sink. You can configure multiple fields for the ceOverrides definition. A ceOverrides definition supports the following fields: Field Description Required or optional extensions Specifies which attributes are added or overridden on the outbound event. Each extensions key-value pair is set independently on the event as an attribute extension. Optional Note Only valid CloudEvent attribute names are allowed as extensions. You cannot set the spec defined attributes from the extensions override configuration. For example, you can not modify the type attribute. CloudEvent Overrides example apiVersion: sources.knative.dev/v1 kind: SinkBinding metadata: name: bind-heartbeat spec: ... ceOverrides: extensions: extra: this is an extra attribute additional: 42 This sets the K_CE_OVERRIDES environment variable on the subject : Example output { "extensions": { "extra": "this is an extra attribute", "additional": "42" } } 5.10.1.4.3. The include label To use a sink binding, you need to do assign the bindings.knative.dev/include: "true" label to either the resource or the namespace that the resource is included in. If the resource definition does not include the label, a cluster administrator can attach it to the namespace by running: USD oc label namespace <namespace> bindings.knative.dev/include=true 5.10.2. Container source Container sources create a container image that generates events and sends events to a sink. You can use a container source to create a custom event source, by creating a container image and a ContainerSource object that uses your image URI. 5.10.2.1. Guidelines for creating a container image Two environment variables are injected by the container source controller: K_SINK and K_CE_OVERRIDES . These variables are resolved from the sink and ceOverrides spec, respectively. Events are sent to the sink URI specified in the K_SINK environment variable. The message must be sent as a POST using the CloudEvent HTTP format. Example container images The following is an example of a heartbeats container image: package main import ( "context" "encoding/json" "flag" "fmt" "log" "os" "strconv" "time" duckv1 "knative.dev/pkg/apis/duck/v1" cloudevents "github.com/cloudevents/sdk-go/v2" "github.com/kelseyhightower/envconfig" ) type Heartbeat struct { Sequence int `json:"id"` Label string `json:"label"` } var ( eventSource string eventType string sink string label string periodStr string ) func init() { flag.StringVar(&eventSource, "eventSource", "", "the event-source (CloudEvents)") flag.StringVar(&eventType, "eventType", "dev.knative.eventing.samples.heartbeat", "the event-type (CloudEvents)") flag.StringVar(&sink, "sink", "", "the host url to heartbeat to") flag.StringVar(&label, "label", "", "a special label") flag.StringVar(&periodStr, "period", "5", "the number of seconds between heartbeats") } type envConfig struct { // Sink URL where to send heartbeat cloud events Sink string `envconfig:"K_SINK"` // CEOverrides are the CloudEvents overrides to be applied to the outbound event. CEOverrides string `envconfig:"K_CE_OVERRIDES"` // Name of this pod. Name string `envconfig:"POD_NAME" required:"true"` // Namespace this pod exists in. Namespace string `envconfig:"POD_NAMESPACE" required:"true"` // Whether to run continuously or exit. OneShot bool `envconfig:"ONE_SHOT" default:"false"` } func main() { flag.Parse() var env envConfig if err := envconfig.Process("", &env); err != nil { log.Printf("[ERROR] Failed to process env var: %s", err) os.Exit(1) } if env.Sink != "" { sink = env.Sink } var ceOverrides *duckv1.CloudEventOverrides if len(env.CEOverrides) > 0 { overrides := duckv1.CloudEventOverrides{} err := json.Unmarshal([]byte(env.CEOverrides), &overrides) if err != nil { log.Printf("[ERROR] Unparseable CloudEvents overrides %s: %v", env.CEOverrides, err) os.Exit(1) } ceOverrides = &overrides } p, err := cloudevents.NewHTTP(cloudevents.WithTarget(sink)) if err != nil { log.Fatalf("failed to create http protocol: %s", err.Error()) } c, err := cloudevents.NewClient(p, cloudevents.WithUUIDs(), cloudevents.WithTimeNow()) if err != nil { log.Fatalf("failed to create client: %s", err.Error()) } var period time.Duration if p, err := strconv.Atoi(periodStr); err != nil { period = time.Duration(5) * time.Second } else { period = time.Duration(p) * time.Second } if eventSource == "" { eventSource = fmt.Sprintf("https://knative.dev/eventing-contrib/cmd/heartbeats/#%s/%s", env.Namespace, env.Name) log.Printf("Heartbeats Source: %s", eventSource) } if len(label) > 0 && label[0] == '"' { label, _ = strconv.Unquote(label) } hb := &Heartbeat{ Sequence: 0, Label: label, } ticker := time.NewTicker(period) for { hb.Sequence++ event := cloudevents.NewEvent("1.0") event.SetType(eventType) event.SetSource(eventSource) event.SetExtension("the", 42) event.SetExtension("heart", "yes") event.SetExtension("beats", true) if ceOverrides != nil && ceOverrides.Extensions != nil { for n, v := range ceOverrides.Extensions { event.SetExtension(n, v) } } if err := event.SetData(cloudevents.ApplicationJSON, hb); err != nil { log.Printf("failed to set cloudevents data: %s", err.Error()) } log.Printf("sending cloudevent to %s", sink) if res := c.Send(context.Background(), event); !cloudevents.IsACK(res) { log.Printf("failed to send cloudevent: %v", res) } if env.OneShot { return } // Wait for tick <-ticker.C } } The following is an example of a container source that references the heartbeats container image: apiVersion: sources.knative.dev/v1 kind: ContainerSource metadata: name: test-heartbeats spec: template: spec: containers: # This corresponds to a heartbeats image URI that you have built and published - image: gcr.io/knative-releases/knative.dev/eventing/cmd/heartbeats name: heartbeats args: - --period=1 env: - name: POD_NAME value: "example-pod" - name: POD_NAMESPACE value: "event-test" sink: ref: apiVersion: serving.knative.dev/v1 kind: Service name: example-service ... 5.10.2.2. Creating and managing container sources by using the Knative CLI You can use the kn source container commands to create and manage container sources by using the Knative ( kn ) CLI. Using the Knative CLI to create event sources provides a more streamlined and intuitive user interface than modifying YAML files directly. Create a container source USD kn source container create <container_source_name> --image <image_uri> --sink <sink> Delete a container source USD kn source container delete <container_source_name> Describe a container source USD kn source container describe <container_source_name> List existing container sources USD kn source container list List existing container sources in YAML format USD kn source container list -o yaml Update a container source This command updates the image URI for an existing container source: USD kn source container update <container_source_name> --image <image_uri> 5.10.2.3. Creating a container source by using the web console After Knative Eventing is installed on your cluster, you can create a container source by using the web console. Using the OpenShift Container Platform web console provides a streamlined and intuitive user interface to create an event source. Prerequisites You have logged in to the OpenShift Container Platform web console. The OpenShift Serverless Operator, Knative Serving, and Knative Eventing are installed on your OpenShift Container Platform cluster. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. Procedure In the Developer perspective, navigate to +Add Event Source . The Event Sources page is displayed. Select Container Source and then click Create Event Source . The Create Event Source page is displayed. Configure the Container Source settings by using the Form view or YAML view : Note You can switch between the Form view and YAML view . The data is persisted when switching between the views. In the Image field, enter the URI of the image that you want to run in the container created by the container source. In the Name field, enter the name of the image. Optional: In the Arguments field, enter any arguments to be passed to the container. Optional: In the Environment variables field, add any environment variables to set in the container. In the Sink section, add a sink where events from the container source are routed to. If you are using the Form view, you can choose from the following options: Select Resource to use a channel, broker, or service as a sink for the event source. Select URI to specify where the events from the container source are routed to. After you have finished configuring the container source, click Create . 5.10.2.4. Container source reference You can use a container as an event source, by creating a ContainerSource object. You can configure multiple parameters when creating a ContainerSource object. ContainerSource objects support the following fields: Field Description Required or optional apiVersion Specifies the API version, for example sources.knative.dev/v1 . Required kind Identifies this resource object as a ContainerSource object. Required metadata Specifies metadata that uniquely identifies the ContainerSource object. For example, a name . Required spec Specifies the configuration information for this ContainerSource object. Required spec.sink A reference to an object that resolves to a URI to use as the sink. Required spec.template A template spec for the ContainerSource object. Required spec.ceOverrides Defines overrides to control the output format and modifications to the event sent to the sink. Optional Template parameter example apiVersion: sources.knative.dev/v1 kind: ContainerSource metadata: name: test-heartbeats spec: template: spec: containers: - image: quay.io/openshift-knative/heartbeats:latest name: heartbeats args: - --period=1 env: - name: POD_NAME value: "mypod" - name: POD_NAMESPACE value: "event-test" ... 5.10.2.4.1. CloudEvent overrides A ceOverrides definition provides overrides that control the CloudEvent's output format and modifications sent to the sink. You can configure multiple fields for the ceOverrides definition. A ceOverrides definition supports the following fields: Field Description Required or optional extensions Specifies which attributes are added or overridden on the outbound event. Each extensions key-value pair is set independently on the event as an attribute extension. Optional Note Only valid CloudEvent attribute names are allowed as extensions. You cannot set the spec defined attributes from the extensions override configuration. For example, you can not modify the type attribute. CloudEvent Overrides example apiVersion: sources.knative.dev/v1 kind: ContainerSource metadata: name: test-heartbeats spec: ... ceOverrides: extensions: extra: this is an extra attribute additional: 42 This sets the K_CE_OVERRIDES environment variable on the subject : Example output { "extensions": { "extra": "this is an extra attribute", "additional": "42" } } 5.11. Creating channels Channels are custom resources that define a single event-forwarding and persistence layer. After events have been sent to a channel from an event source or producer, these events can be sent to multiple Knative services or other sinks by using a subscription. You can create channels by instantiating a supported Channel object, and configure re-delivery attempts by modifying the delivery spec in a Subscription object. 5.11.1. Creating a channel by using the web console Using the OpenShift Container Platform web console provides a streamlined and intuitive user interface to create a channel. After Knative Eventing is installed on your cluster, you can create a channel by using the web console. Prerequisites You have logged in to the OpenShift Container Platform web console. The OpenShift Serverless Operator and Knative Eventing are installed on your OpenShift Container Platform cluster. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. Procedure In the Developer perspective, navigate to +Add Channel . Select the type of Channel object that you want to create in the Type list. Click Create . Verification Confirm that the channel now exists by navigating to the Topology page. 5.11.2. Creating a channel by using the Knative CLI Using the Knative ( kn ) CLI to create channels provides a more streamlined and intuitive user interface than modifying YAML files directly. You can use the kn channel create command to create a channel. Prerequisites The OpenShift Serverless Operator and Knative Eventing are installed on the cluster. You have installed the Knative ( kn ) CLI. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. Procedure Create a channel: USD kn channel create <channel_name> --type <channel_type> The channel type is optional, but where specified, must be given in the format Group:Version:Kind . For example, you can create an InMemoryChannel object: USD kn channel create mychannel --type messaging.knative.dev:v1:InMemoryChannel Example output Channel 'mychannel' created in namespace 'default'. Verification To confirm that the channel now exists, list the existing channels and inspect the output: USD kn channel list Example output kn channel list NAME TYPE URL AGE READY REASON mychannel InMemoryChannel http://mychannel-kn-channel.default.svc.cluster.local 93s True Deleting a channel Delete a channel: USD kn channel delete <channel_name> 5.11.3. Creating a default implementation channel by using YAML Creating Knative resources by using YAML files uses a declarative API, which enables you to describe channels declaratively and in a reproducible manner. To create a serverless channel by using YAML, you must create a YAML file that defines a Channel object, then apply it by using the oc apply command. Prerequisites The OpenShift Serverless Operator and Knative Eventing are installed on the cluster. Install the OpenShift CLI ( oc ). You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. Procedure Create a Channel object as a YAML file: apiVersion: messaging.knative.dev/v1 kind: Channel metadata: name: example-channel namespace: default Apply the YAML file: USD oc apply -f <filename> 5.11.4. Creating a Kafka channel by using YAML Creating Knative resources by using YAML files uses a declarative API, which enables you to describe channels declaratively and in a reproducible manner. You can create a Knative Eventing channel that is backed by Kafka topics by creating a Kafka channel. To create a Kafka channel by using YAML, you must create a YAML file that defines a KafkaChannel object, then apply it by using the oc apply command. Prerequisites The OpenShift Serverless Operator, Knative Eventing, and the KnativeKafka custom resource are installed on your OpenShift Container Platform cluster. Install the OpenShift CLI ( oc ). You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. Procedure Create a KafkaChannel object as a YAML file: apiVersion: messaging.knative.dev/v1beta1 kind: KafkaChannel metadata: name: example-channel namespace: default spec: numPartitions: 3 replicationFactor: 1 Important Only the v1beta1 version of the API for KafkaChannel objects on OpenShift Serverless is supported. Do not use the v1alpha1 version of this API, as this version is now deprecated. Apply the KafkaChannel YAML file: USD oc apply -f <filename> 5.11.5. steps After you have created a channel, create a subscription that allows event sinks to subscribe to channels and receive events. Configure event delivery parameters that are applied in cases where an event fails to be delivered to an event sink. See Examples of configuring event delivery parameters . 5.12. Creating and managing subscriptions After you have created a channel and an event sink, you can create a subscription to enable event delivery. Subscriptions are created by configuring a Subscription object, which specifies the channel and the sink (also known as a subscriber ) to deliver events to. 5.12.1. Creating a subscription by using the web console After you have created a channel and an event sink, you can create a subscription to enable event delivery. Using the OpenShift Container Platform web console provides a streamlined and intuitive user interface to create a subscription. Prerequisites The OpenShift Serverless Operator, Knative Serving, and Knative Eventing are installed on your OpenShift Container Platform cluster. You have logged in to the web console. You have created an event sink, such as a Knative service, and a channel. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. Procedure In the Developer perspective, navigate to the Topology page. Create a subscription using one of the following methods: Hover over the channel that you want to create a subscription for, and drag the arrow. The Add Subscription option is displayed. Select your sink in the Subscriber list. Click Add . If the service is available in the Topology view under the same namespace or project as the channel, click on the channel that you want to create a subscription for, and drag the arrow directly to a service to immediately create a subscription from the channel to that service. Verification After the subscription has been created, you can see it represented as a line that connects the channel to the service in the Topology view: 5.12.2. Creating a subscription by using YAML After you have created a channel and an event sink, you can create a subscription to enable event delivery. Creating Knative resources by using YAML files uses a declarative API, which enables you to describe subscriptions declaratively and in a reproducible manner. To create a subscription by using YAML, you must create a YAML file that defines a Subscription object, then apply it by using the oc apply command. Prerequisites The OpenShift Serverless Operator and Knative Eventing are installed on the cluster. Install the OpenShift CLI ( oc ). You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. Procedure Create a Subscription object: Create a YAML file and copy the following sample code into it: apiVersion: messaging.knative.dev/v1beta1 kind: Subscription metadata: name: my-subscription 1 namespace: default spec: channel: 2 apiVersion: messaging.knative.dev/v1beta1 kind: Channel name: example-channel delivery: 3 deadLetterSink: ref: apiVersion: serving.knative.dev/v1 kind: Service name: error-handler subscriber: 4 ref: apiVersion: serving.knative.dev/v1 kind: Service name: event-display 1 Name of the subscription. 2 Configuration settings for the channel that the subscription connects to. 3 Configuration settings for event delivery. This tells the subscription what happens to events that cannot be delivered to the subscriber. When this is configured, events that failed to be consumed are sent to the deadLetterSink . The event is dropped, no re-delivery of the event is attempted, and an error is logged in the system. The deadLetterSink value must be a Destination . 4 Configuration settings for the subscriber. This is the event sink that events are delivered to from the channel. Apply the YAML file: USD oc apply -f <filename> 5.12.3. Creating a subscription by using the Knative CLI After you have created a channel and an event sink, you can create a subscription to enable event delivery. Using the Knative ( kn ) CLI to create subscriptions provides a more streamlined and intuitive user interface than modifying YAML files directly. You can use the kn subscription create command with the appropriate flags to create a subscription. Prerequisites The OpenShift Serverless Operator and Knative Eventing are installed on your OpenShift Container Platform cluster. You have installed the Knative ( kn ) CLI. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. Procedure Create a subscription to connect a sink to a channel: USD kn subscription create <subscription_name> \ --channel <group:version:kind>:<channel_name> \ 1 --sink <sink_prefix>:<sink_name> \ 2 --sink-dead-letter <sink_prefix>:<sink_name> 3 1 --channel specifies the source for cloud events that should be processed. You must provide the channel name. If you are not using the default InMemoryChannel channel that is backed by the Channel custom resource, you must prefix the channel name with the <group:version:kind> for the specified channel type. For example, this will be messaging.knative.dev:v1beta1:KafkaChannel for a Kafka backed channel. 2 --sink specifies the target destination to which the event should be delivered. By default, the <sink_name> is interpreted as a Knative service of this name, in the same namespace as the subscription. You can specify the type of the sink by using one of the following prefixes: ksvc A Knative service. channel A channel that should be used as destination. Only default channel types can be referenced here. broker An Eventing broker. 3 Optional: --sink-dead-letter is an optional flag that can be used to specify a sink which events should be sent to in cases where events fail to be delivered. For more information, see the OpenShift Serverless Event delivery documentation. Example command USD kn subscription create mysubscription --channel mychannel --sink ksvc:event-display Example output Subscription 'mysubscription' created in namespace 'default'. Verification To confirm that the channel is connected to the event sink, or subscriber , by a subscription, list the existing subscriptions and inspect the output: USD kn subscription list Example output NAME CHANNEL SUBSCRIBER REPLY DEAD LETTER SINK READY REASON mysubscription Channel:mychannel ksvc:event-display True Deleting a subscription Delete a subscription: USD kn subscription delete <subscription_name> 5.12.4. Describing subscriptions by using the Knative CLI You can use the kn subscription describe command to print information about a subscription in the terminal by using the Knative ( kn ) CLI. Using the Knative CLI to describe subscriptions provides a more streamlined and intuitive user interface than viewing YAML files directly. Prerequisites You have installed the Knative ( kn ) CLI. You have created a subscription in your cluster. Procedure Describe a subscription: USD kn subscription describe <subscription_name> Example output Name: my-subscription Namespace: default Annotations: messaging.knative.dev/creator=openshift-user, messaging.knative.dev/lastModifier=min ... Age: 43s Channel: Channel:my-channel (messaging.knative.dev/v1) Subscriber: URI: http://edisplay.default.example.com Reply: Name: default Resource: Broker (eventing.knative.dev/v1) DeadLetterSink: Name: my-sink Resource: Service (serving.knative.dev/v1) Conditions: OK TYPE AGE REASON ++ Ready 43s ++ AddedToChannel 43s ++ ChannelReady 43s ++ ReferencesResolved 43s 5.12.5. Listing subscriptions by using the Knative CLI You can use the kn subscription list command to list existing subscriptions on your cluster by using the Knative ( kn ) CLI. Using the Knative CLI to list subscriptions provides a streamlined and intuitive user interface. Prerequisites You have installed the Knative ( kn ) CLI. Procedure List subscriptions on your cluster: USD kn subscription list Example output NAME CHANNEL SUBSCRIBER REPLY DEAD LETTER SINK READY REASON mysubscription Channel:mychannel ksvc:event-display True 5.12.6. Updating subscriptions by using the Knative CLI You can use the kn subscription update command as well as the appropriate flags to update a subscription from the terminal by using the Knative ( kn ) CLI. Using the Knative CLI to update subscriptions provides a more streamlined and intuitive user interface than updating YAML files directly. Prerequisites You have installed the Knative ( kn ) CLI. You have created a subscription. Procedure Update a subscription: USD kn subscription update <subscription_name> \ --sink <sink_prefix>:<sink_name> \ 1 --sink-dead-letter <sink_prefix>:<sink_name> 2 1 --sink specifies the updated target destination to which the event should be delivered. You can specify the type of the sink by using one of the following prefixes: ksvc A Knative service. channel A channel that should be used as destination. Only default channel types can be referenced here. broker An Eventing broker. 2 Optional: --sink-dead-letter is an optional flag that can be used to specify a sink which events should be sent to in cases where events fail to be delivered. For more information, see the OpenShift Serverless Event delivery documentation. Example command USD kn subscription update mysubscription --sink ksvc:event-display 5.12.7. steps Configure event delivery parameters that are applied in cases where an event fails to be delivered to an event sink. See Examples of configuring event delivery parameters . 5.13. Creating brokers Knative provides a default, channel-based broker implementation. This channel-based broker can be used for development and testing purposes, but does not provide adequate event delivery guarantees for production environments. If a cluster administrator has configured your OpenShift Serverless deployment to use Kafka as the default broker type, creating a broker by using the default settings creates a Kafka-based broker. If your OpenShift Serverless deployment is not configured to use Kafka broker as the default broker type, the channel-based broker is created when you use the default settings in the following procedures. Important Kafka broker is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process. For more information about the support scope of Red Hat Technology Preview features, see https://access.redhat.com/support/offerings/techpreview/ . 5.13.1. Creating a broker by using the Knative CLI Brokers can be used in combination with triggers to deliver events from an event source to an event sink. Using the Knative ( kn ) CLI to create brokers provides a more streamlined and intuitive user interface over modifying YAML files directly. You can use the kn broker create command to create a broker. Prerequisites The OpenShift Serverless Operator and Knative Eventing are installed on your OpenShift Container Platform cluster. You have installed the Knative ( kn ) CLI. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. Procedure Create a broker: USD kn broker create <broker_name> Verification Use the kn command to list all existing brokers: USD kn broker list Example output NAME URL AGE CONDITIONS READY REASON default http://broker-ingress.knative-eventing.svc.cluster.local/test/default 45s 5 OK / 5 True Optional: If you are using the OpenShift Container Platform web console, you can navigate to the Topology view in the Developer perspective, and observe that the broker exists: 5.13.2. Creating a broker by annotating a trigger Brokers can be used in combination with triggers to deliver events from an event source to an event sink. You can create a broker by adding the eventing.knative.dev/injection: enabled annotation to a Trigger object. Important If you create a broker by using the eventing.knative.dev/injection: enabled annotation, you cannot delete this broker without cluster administrator permissions. If you delete the broker without having a cluster administrator remove this annotation first, the broker is created again after deletion. Prerequisites The OpenShift Serverless Operator and Knative Eventing are installed on your OpenShift Container Platform cluster. Install the OpenShift CLI ( oc ). You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. Procedure Create a Trigger object as a YAML file that has the eventing.knative.dev/injection: enabled annotation: apiVersion: eventing.knative.dev/v1 kind: Trigger metadata: annotations: eventing.knative.dev/injection: enabled name: <trigger_name> spec: broker: default subscriber: 1 ref: apiVersion: serving.knative.dev/v1 kind: Service name: <service_name> 1 Specify details about the event sink, or subscriber , that the trigger sends events to. Apply the Trigger YAML file: USD oc apply -f <filename> Verification You can verify that the broker has been created successfully by using the oc CLI, or by observing it in the Topology view in the web console. Enter the following oc command to get the broker: USD oc -n <namespace> get broker default Example output NAME READY REASON URL AGE default True http://broker-ingress.knative-eventing.svc.cluster.local/test/default 3m56s Optional: If you are using the OpenShift Container Platform web console, you can navigate to the Topology view in the Developer perspective, and observe that the broker exists: 5.13.3. Creating a broker by labeling a namespace Brokers can be used in combination with triggers to deliver events from an event source to an event sink. You can create the default broker automatically by labelling a namespace that you own or have write permissions for. Note Brokers created using this method are not removed if you remove the label. You must manually delete them. Prerequisites The OpenShift Serverless Operator and Knative Eventing are installed on your OpenShift Container Platform cluster. Install the OpenShift CLI ( oc ). You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. Procedure Label a namespace with eventing.knative.dev/injection=enabled : USD oc label namespace <namespace> eventing.knative.dev/injection=enabled Verification You can verify that the broker has been created successfully by using the oc CLI, or by observing it in the Topology view in the web console. Use the oc command to get the broker: USD oc -n <namespace> get broker <broker_name> Example command USD oc -n default get broker default Example output NAME READY REASON URL AGE default True http://broker-ingress.knative-eventing.svc.cluster.local/test/default 3m56s Optional: If you are using the OpenShift Container Platform web console, you can navigate to the Topology view in the Developer perspective, and observe that the broker exists: 5.13.4. Deleting a broker that was created by injection If you create a broker by injection and later want to delete it, you must delete it manually. Brokers created by using a namespace label or trigger annotation are not deleted permanently if you remove the label or annotation. Prerequisites Install the OpenShift CLI ( oc ). Procedure Remove the eventing.knative.dev/injection=enabled label from the namespace: USD oc label namespace <namespace> eventing.knative.dev/injection- Removing the annotation prevents Knative from recreating the broker after you delete it. Delete the broker from the selected namespace: USD oc -n <namespace> delete broker <broker_name> Verification Use the oc command to get the broker: USD oc -n <namespace> get broker <broker_name> Example command USD oc -n default get broker default Example output No resources found. Error from server (NotFound): brokers.eventing.knative.dev "default" not found 5.13.5. Creating a Kafka broker when it is not configured as the default broker type If your OpenShift Serverless deployment is not configured to use Kafka broker as the default broker type, you can use one of the following procedures to create a Kafka-based broker. Important Kafka broker is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process. For more information about the support scope of Red Hat Technology Preview features, see https://access.redhat.com/support/offerings/techpreview/ . 5.13.5.1. Creating a Kafka broker by using YAML Creating Knative resources by using YAML files uses a declarative API, which enables you to describe applications declaratively and in a reproducible manner. To create a Kafka broker by using YAML, you must create a YAML file that defines a Broker object, then apply it by using the oc apply command. Prerequisites The OpenShift Serverless Operator, Knative Eventing, and the KnativeKafka custom resource are installed on your OpenShift Container Platform cluster. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. You have installed the OpenShift CLI ( oc ). Procedure Create a Kafka-based broker as a YAML file: apiVersion: eventing.knative.dev/v1 kind: Broker metadata: annotations: eventing.knative.dev/broker.class: Kafka 1 name: example-kafka-broker spec: config: apiVersion: v1 kind: ConfigMap name: kafka-broker-config 2 namespace: knative-eventing 1 The broker class. If not specified, brokers use the default class as configured by cluster administrators. To use the Kafka broker, this value must be Kafka . 2 The default config map for Knative Kafka brokers. This config map is created when the Kafka broker functionality is enabled on the cluster by a cluster administrator. Apply the Kafka-based broker YAML file: USD oc apply -f <filename> 5.13.5.2. Creating a Kafka broker that uses an externally managed Kafka topic If you want to use a Kafka broker without allowing it to create its own internal topic, you can use an externally managed Kafka topic instead. To do this, you must create a Kafka Broker object that uses the kafka.eventing.knative.dev/external.topic annotation. Prerequisites The OpenShift Serverless Operator, Knative Eventing, and the KnativeKafka custom resource are installed on your OpenShift Container Platform cluster. You have access to a Kafka instance such as Red Hat AMQ Streams , and have created a Kafka topic. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. You have installed the OpenShift CLI ( oc ). Procedure Create a Kafka-based broker as a YAML file: apiVersion: eventing.knative.dev/v1 kind: Broker metadata: annotations: eventing.knative.dev/broker.class: Kafka 1 kafka.eventing.knative.dev/external.topic: <topic_name> 2 ... 1 The broker class. If not specified, brokers use the default class as configured by cluster administrators. To use the Kafka broker, this value must be Kafka . 2 The name of the Kafka topic that you want to use. Apply the Kafka-based broker YAML file: USD oc apply -f <filename> 5.13.6. Managing brokers The Knative ( kn ) CLI provides commands that can be used to describe and list existing brokers. 5.13.6.1. Listing existing brokers by using the Knative CLI Using the Knative ( kn ) CLI to list brokers provides a streamlined and intuitive user interface. You can use the kn broker list command to list existing brokers in your cluster by using the Knative CLI. Prerequisites The OpenShift Serverless Operator and Knative Eventing are installed on your OpenShift Container Platform cluster. You have installed the Knative ( kn ) CLI. Procedure List all existing brokers: USD kn broker list Example output NAME URL AGE CONDITIONS READY REASON default http://broker-ingress.knative-eventing.svc.cluster.local/test/default 45s 5 OK / 5 True 5.13.6.2. Describing an existing broker by using the Knative CLI Using the Knative ( kn ) CLI to describe brokers provides a streamlined and intuitive user interface. You can use the kn broker describe command to print information about existing brokers in your cluster by using the Knative CLI. Prerequisites The OpenShift Serverless Operator and Knative Eventing are installed on your OpenShift Container Platform cluster. You have installed the Knative ( kn ) CLI. Procedure Describe an existing broker: USD kn broker describe <broker_name> Example command using default broker USD kn broker describe default Example output Name: default Namespace: default Annotations: eventing.knative.dev/broker.class=MTChannelBasedBroker, eventing.knative.dev/creato ... Age: 22s Address: URL: http://broker-ingress.knative-eventing.svc.cluster.local/default/default Conditions: OK TYPE AGE REASON ++ Ready 22s ++ Addressable 22s ++ FilterReady 22s ++ IngressReady 22s ++ TriggerChannelReady 22s 5.13.7. steps Configure event delivery parameters that are applied in cases where an event fails to be delivered to an event sink. See Examples of configuring event delivery parameters . 5.13.8. Additional resources Configuring the default broker class Triggers Event sources Event delivery Kafka broker Configuring Knative Kafka 5.14. Triggers Brokers can be used in combination with triggers to deliver events from an event source to an event sink. Events are sent from an event source to a broker as an HTTP POST request. After events have entered the broker, they can be filtered by CloudEvent attributes using triggers, and sent as an HTTP POST request to an event sink. If you are using a Kafka broker, you can configure the delivery order of events from triggers to event sinks. See Configuring event delivery ordering for triggers . 5.14.1. Creating a trigger by using the web console Using the OpenShift Container Platform web console provides a streamlined and intuitive user interface to create a trigger. After Knative Eventing is installed on your cluster and you have created a broker, you can create a trigger by using the web console. Prerequisites The OpenShift Serverless Operator, Knative Serving, and Knative Eventing are installed on your OpenShift Container Platform cluster. You have logged in to the web console. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. You have created a broker and a Knative service or other event sink to connect to the trigger. Procedure In the Developer perspective, navigate to the Topology page. Hover over the broker that you want to create a trigger for, and drag the arrow. The Add Trigger option is displayed. Click Add Trigger . Select your sink in the Subscriber list. Click Add . Verification After the subscription has been created, you can view it in the Topology page, where it is represented as a line that connects the broker to the event sink. Deleting a trigger In the Developer perspective, navigate to the Topology page. Click on the trigger that you want to delete. In the Actions context menu, select Delete Trigger . 5.14.2. Creating a trigger by using the Knative CLI Using the Knative ( kn ) CLI to create triggers provides a more streamlined and intuitive user interface over modifying YAML files directly. You can use the kn trigger create command to create a trigger. Prerequisites The OpenShift Serverless Operator and Knative Eventing are installed on your OpenShift Container Platform cluster. You have installed the Knative ( kn ) CLI. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. Procedure Create a trigger: USD kn trigger create <trigger_name> --broker <broker_name> --filter <key=value> --sink <sink_name> Alternatively, you can create a trigger and simultaneously create the default broker using broker injection: USD kn trigger create <trigger_name> --inject-broker --filter <key=value> --sink <sink_name> By default, triggers forward all events sent to a broker to sinks that are subscribed to that broker. Using the --filter attribute for triggers allows you to filter events from a broker, so that subscribers will only receive a subset of events based on your defined criteria. 5.14.3. Listing triggers by using the Knative CLI Using the Knative ( kn ) CLI to list triggers provides a streamlined and intuitive user interface. You can use the kn trigger list command to list existing triggers in your cluster. Prerequisites The OpenShift Serverless Operator and Knative Eventing are installed on your OpenShift Container Platform cluster. You have installed the Knative ( kn ) CLI. Procedure Print a list of available triggers: USD kn trigger list Example output NAME BROKER SINK AGE CONDITIONS READY REASON email default ksvc:edisplay 4s 5 OK / 5 True ping default ksvc:edisplay 32s 5 OK / 5 True Optional: Print a list of triggers in JSON format: USD kn trigger list -o json 5.14.4. Describing a trigger by using the Knative CLI Using the Knative ( kn ) CLI to describe triggers provides a streamlined and intuitive user interface. You can use the kn trigger describe command to print information about existing triggers in your cluster by using the Knative CLI. Prerequisites The OpenShift Serverless Operator and Knative Eventing are installed on your OpenShift Container Platform cluster. You have installed the Knative ( kn ) CLI. You have created a trigger. Procedure Enter the command: USD kn trigger describe <trigger_name> Example output Name: ping Namespace: default Labels: eventing.knative.dev/broker=default Annotations: eventing.knative.dev/creator=kube:admin, eventing.knative.dev/lastModifier=kube:admin Age: 2m Broker: default Filter: type: dev.knative.event Sink: Name: edisplay Namespace: default Resource: Service (serving.knative.dev/v1) Conditions: OK TYPE AGE REASON ++ Ready 2m ++ BrokerReady 2m ++ DependencyReady 2m ++ Subscribed 2m ++ SubscriberResolved 2m 5.14.5. Filtering events with triggers by using the Knative CLI Using the Knative ( kn ) CLI to filter events by using triggers provides a streamlined and intuitive user interface. You can use the kn trigger create command, along with the appropriate flags, to filter events by using triggers. In the following trigger example, only events with the attribute type: dev.knative.samples.helloworld are sent to the event sink: USD kn trigger create <trigger_name> --broker <broker_name> --filter type=dev.knative.samples.helloworld --sink ksvc:<service_name> You can also filter events by using multiple attributes. The following example shows how to filter events using the type, source, and extension attributes: USD kn trigger create <trigger_name> --broker <broker_name> --sink ksvc:<service_name> \ --filter type=dev.knative.samples.helloworld \ --filter source=dev.knative.samples/helloworldsource \ --filter myextension=my-extension-value 5.14.6. Updating a trigger by using the Knative CLI Using the Knative ( kn ) CLI to update triggers provides a streamlined and intuitive user interface. You can use the kn trigger update command with certain flags to update attributes for a trigger. Prerequisites The OpenShift Serverless Operator and Knative Eventing are installed on your OpenShift Container Platform cluster. You have installed the Knative ( kn ) CLI. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. Procedure Update a trigger: USD kn trigger update <trigger_name> --filter <key=value> --sink <sink_name> [flags] You can update a trigger to filter exact event attributes that match incoming events. For example, using the type attribute: USD kn trigger update <trigger_name> --filter type=knative.dev.event You can remove a filter attribute from a trigger. For example, you can remove the filter attribute with key type : USD kn trigger update <trigger_name> --filter type- You can use the --sink parameter to change the event sink of a trigger: USD kn trigger update <trigger_name> --sink ksvc:my-event-sink 5.14.7. Deleting a trigger by using the Knative CLI Using the Knative ( kn ) CLI to delete a trigger provides a streamlined and intuitive user interface. You can use the kn trigger delete command to delete a trigger. Prerequisites The OpenShift Serverless Operator and Knative Eventing are installed on your OpenShift Container Platform cluster. You have installed the Knative ( kn ) CLI. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. Procedure Delete a trigger: USD kn trigger delete <trigger_name> Verification List existing triggers: USD kn trigger list Verify that the trigger no longer exists: Example output No triggers found. 5.14.8. Configuring event delivery ordering for triggers If you are using a Kafka broker, you can configure the delivery order of events from triggers to event sinks. Prerequisites The OpenShift Serverless Operator, Knative Eventing, and Knative Kafka are installed on your OpenShift Container Platform cluster. Kafka broker is enabled for use on your cluster, and you have created a Kafka broker. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. You have installed the OpenShift ( oc ) CLI. Procedure Create or modify a Trigger object and set the kafka.eventing.knative.dev/delivery.order annotation: apiVersion: eventing.knative.dev/v1 kind: Trigger metadata: name: <trigger_name> annotations: kafka.eventing.knative.dev/delivery.order: ordered ... The supported consumer delivery guarantees are: unordered An unordered consumer is a non-blocking consumer that delivers messages unordered, while preserving proper offset management. ordered An ordered consumer is a per-partition blocking consumer that waits for a successful response from the CloudEvent subscriber before it delivers the message of the partition. The default ordering guarantee is unordered . Apply the Trigger object: USD oc apply -f <filename> 5.14.9. steps Configure event delivery parameters that are applied in cases where an event fails to be delivered to an event sink. See Examples of configuring event delivery parameters . 5.15. Using Knative Kafka Knative Kafka provides integration options for you to use supported versions of the Apache Kafka message streaming platform with OpenShift Serverless. Kafka provides options for event source, channel, broker, and event sink capabilities. Knative Kafka functionality is available in an OpenShift Serverless installation if a cluster administrator has installed the KnativeKafka custom resource . Note Knative Kafka is not currently supported for IBM Z and IBM Power Systems. Knative Kafka provides additional options, such as: Kafka source Kafka channel Kafka broker (Technology Preview) Kafka sink (Technology Preview) 5.15.1. Kafka event delivery and retries Using Kafka components in an event-driven architecture provides "at least once" event delivery. This means that operations are retried until a return code value is received. This makes applications more resilient to lost events; however, it might result in duplicate events being sent. For the Kafka event source, there is a fixed number of retries for event delivery by default. For Kafka channels, retries are only performed if they are configured in the Kafka channel Delivery spec. See the Event delivery documentation for more information about delivery guarantees. 5.15.2. Kafka source You can create a Kafka source that reads events from an Apache Kafka cluster and passes these events to a sink. You can create a Kafka source by using the OpenShift Container Platform web console, the Knative ( kn ) CLI, or by creating a KafkaSource object directly as a YAML file and using the OpenShift CLI ( oc ) to apply it. 5.15.2.1. Creating a Kafka event source by using the web console After Knative Kafka is installed on your cluster, you can create a Kafka source by using the web console. Using the OpenShift Container Platform web console provides a streamlined and intuitive user interface to create a Kafka source. Prerequisites The OpenShift Serverless Operator, Knative Eventing, and the KnativeKafka custom resource are installed on your cluster. You have logged in to the web console. You have access to a Red Hat AMQ Streams (Kafka) cluster that produces the Kafka messages you want to import. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. Procedure In the Developer perspective, navigate to the Add page and select Event Source . In the Event Sources page, select Kafka Source in the Type section. Configure the Kafka Source settings: Add a comma-separated list of Bootstrap Servers . Add a comma-separated list of Topics . Add a Consumer Group . Select the Service Account Name for the service account that you created. Select the Sink for the event source. A Sink can be either a Resource , such as a channel, broker, or service, or a URI . Enter a Name for the Kafka event source. Click Create . Verification You can verify that the Kafka event source was created and is connected to the sink by viewing the Topology page. In the Developer perspective, navigate to Topology . View the Kafka event source and sink. 5.15.2.2. Creating a Kafka event source by using the Knative CLI You can use the kn source kafka create command to create a Kafka source by using the Knative ( kn ) CLI. Using the Knative CLI to create event sources provides a more streamlined and intuitive user interface than modifying YAML files directly. Prerequisites The OpenShift Serverless Operator, Knative Eventing, Knative Serving, and the KnativeKafka custom resource (CR) are installed on your cluster. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. You have access to a Red Hat AMQ Streams (Kafka) cluster that produces the Kafka messages you want to import. You have installed the Knative ( kn ) CLI. Optional: You have installed the OpenShift CLI ( oc ) if you want to use the verification steps in this procedure. Procedure To verify that the Kafka event source is working, create a Knative service that dumps incoming events into the service logs: USD kn service create event-display \ --image quay.io/openshift-knative/knative-eventing-sources-event-display Create a KafkaSource CR: USD kn source kafka create <kafka_source_name> \ --servers <cluster_kafka_bootstrap>.kafka.svc:9092 \ --topics <topic_name> --consumergroup my-consumer-group \ --sink event-display Note Replace the placeholder values in this command with values for your source name, bootstrap servers, and topics. The --servers , --topics , and --consumergroup options specify the connection parameters to the Kafka cluster. The --consumergroup option is optional. Optional: View details about the KafkaSource CR you created: USD kn source kafka describe <kafka_source_name> Example output Name: example-kafka-source Namespace: kafka Age: 1h BootstrapServers: example-cluster-kafka-bootstrap.kafka.svc:9092 Topics: example-topic ConsumerGroup: example-consumer-group Sink: Name: event-display Namespace: default Resource: Service (serving.knative.dev/v1) Conditions: OK TYPE AGE REASON ++ Ready 1h ++ Deployed 1h ++ SinkProvided 1h Verification steps Trigger the Kafka instance to send a message to the topic: USD oc -n kafka run kafka-producer \ -ti --image=quay.io/strimzi/kafka:latest-kafka-2.7.0 --rm=true \ --restart=Never -- bin/kafka-console-producer.sh \ --broker-list <cluster_kafka_bootstrap>:9092 --topic my-topic Enter the message in the prompt. This command assumes that: The Kafka cluster is installed in the kafka namespace. The KafkaSource object has been configured to use the my-topic topic. Verify that the message arrived by viewing the logs: USD oc logs USD(oc get pod -o name | grep event-display) -c user-container Example output ☁\ufe0f cloudevents.Event Validation: valid Context Attributes, specversion: 1.0 type: dev.knative.kafka.event source: /apis/v1/namespaces/default/kafkasources/example-kafka-source#example-topic subject: partition:46#0 id: partition:46/offset:0 time: 2021-03-10T11:21:49.4Z Extensions, traceparent: 00-161ff3815727d8755848ec01c866d1cd-7ff3916c44334678-00 Data, Hello! 5.15.2.2.1. Knative CLI sink flag When you create an event source by using the Knative ( kn ) CLI, you can specify a sink where events are sent to from that resource by using the --sink flag. The sink can be any addressable or callable resource that can receive incoming events from other resources. The following example creates a sink binding that uses a service, http://event-display.svc.cluster.local , as the sink: Example command using the sink flag USD kn source binding create bind-heartbeat \ --namespace sinkbinding-example \ --subject "Job:batch/v1:app=heartbeat-cron" \ --sink http://event-display.svc.cluster.local \ 1 --ce-override "sink=bound" 1 svc in http://event-display.svc.cluster.local determines that the sink is a Knative service. Other default sink prefixes include channel , and broker . 5.15.2.3. Creating a Kafka event source by using YAML Creating Knative resources by using YAML files uses a declarative API, which enables you to describe applications declaratively and in a reproducible manner. To create a Kafka source by using YAML, you must create a YAML file that defines a KafkaSource object, then apply it by using the oc apply command. Prerequisites The OpenShift Serverless Operator, Knative Eventing, and the KnativeKafka custom resource are installed on your cluster. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. You have access to a Red Hat AMQ Streams (Kafka) cluster that produces the Kafka messages you want to import. Install the OpenShift CLI ( oc ). Procedure Create a KafkaSource object as a YAML file: apiVersion: sources.knative.dev/v1beta1 kind: KafkaSource metadata: name: <source_name> spec: consumerGroup: <group_name> 1 bootstrapServers: - <list_of_bootstrap_servers> topics: - <list_of_topics> 2 sink: - <list_of_sinks> 3 1 A consumer group is a group of consumers that use the same group ID, and consume data from a topic. 2 A topic provides a destination for the storage of data. Each topic is split into one or more partitions. 3 A sink specifies where events are sent to from a source. Important Only the v1beta1 version of the API for KafkaSource objects on OpenShift Serverless is supported. Do not use the v1alpha1 version of this API, as this version is now deprecated. Example KafkaSource object apiVersion: sources.knative.dev/v1beta1 kind: KafkaSource metadata: name: kafka-source spec: consumerGroup: knative-group bootstrapServers: - my-cluster-kafka-bootstrap.kafka:9092 topics: - knative-demo-topic sink: ref: apiVersion: serving.knative.dev/v1 kind: Service name: event-display Apply the KafkaSource YAML file: USD oc apply -f <filename> Verification Verify that the Kafka event source was created by entering the following command: USD oc get pods Example output NAME READY STATUS RESTARTS AGE kafkasource-kafka-source-5ca0248f-... 1/1 Running 0 13m 5.15.3. Kafka broker Important Kafka broker is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process. For more information about the support scope of Red Hat Technology Preview features, see https://access.redhat.com/support/offerings/techpreview/ . For production-ready Knative Eventing deployments, Red Hat recommends using the Knative Kafka broker implementation. The Kafka broker is an Apache Kafka native implementation of the Knative broker, which sends CloudEvents directly to the Kafka instance. Important The Federal Information Processing Standards (FIPS) mode is disabled for Kafka broker. The Kafka broker has a native integration with Kafka for storing and routing events. This allows better integration with Kafka for the broker and trigger model over other broker types, and reduces network hops. Other benefits of the Kafka broker implementation include: At-least-once delivery guarantees Ordered delivery of events, based on the CloudEvents partitioning extension Control plane high availability A horizontally scalable data plane The Knative Kafka broker stores incoming CloudEvents as Kafka records, using the binary content mode. This means that all CloudEvent attributes and extensions are mapped as headers on the Kafka record, while the data spec of the CloudEvent corresponds to the value of the Kafka record. For information about using Kafka brokers, see Creating brokers . 5.15.4. Creating a Kafka channel by using YAML Creating Knative resources by using YAML files uses a declarative API, which enables you to describe channels declaratively and in a reproducible manner. You can create a Knative Eventing channel that is backed by Kafka topics by creating a Kafka channel. To create a Kafka channel by using YAML, you must create a YAML file that defines a KafkaChannel object, then apply it by using the oc apply command. Prerequisites The OpenShift Serverless Operator, Knative Eventing, and the KnativeKafka custom resource are installed on your OpenShift Container Platform cluster. Install the OpenShift CLI ( oc ). You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. Procedure Create a KafkaChannel object as a YAML file: apiVersion: messaging.knative.dev/v1beta1 kind: KafkaChannel metadata: name: example-channel namespace: default spec: numPartitions: 3 replicationFactor: 1 Important Only the v1beta1 version of the API for KafkaChannel objects on OpenShift Serverless is supported. Do not use the v1alpha1 version of this API, as this version is now deprecated. Apply the KafkaChannel YAML file: USD oc apply -f <filename> 5.15.5. Kafka sink Kafka sinks are a type of event sink that are available if a cluster administrator has enabled Kafka on your cluster. You can send events directly from an event source to a Kafka topic by using a Kafka sink. Important Kafka sink is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process. For more information about the support scope of Red Hat Technology Preview features, see https://access.redhat.com/support/offerings/techpreview/ . 5.15.5.1. Using a Kafka sink You can create an event sink called a Kafka sink that sends events to a Kafka topic. Creating Knative resources by using YAML files uses a declarative API, which enables you to describe applications declaratively and in a reproducible manner. To create a Kafka sink by using YAML, you must create a YAML file that defines a KafkaSink object, then apply it by using the oc apply command. Prerequisites The OpenShift Serverless Operator, Knative Eventing, and the KnativeKafka custom resource (CR) are installed on your cluster. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. You have access to a Red Hat AMQ Streams (Kafka) cluster that produces the Kafka messages you want to import. Install the OpenShift CLI ( oc ). Procedure Create a KafkaSink object definition as a YAML file: Kafka sink YAML apiVersion: eventing.knative.dev/v1alpha1 kind: KafkaSink metadata: name: <sink-name> namespace: <namespace> spec: topic: <topic-name> bootstrapServers: - <bootstrap-server> To create the Kafka sink, apply the KafkaSink YAML file: USD oc apply -f <filename> Configure an event source so that the sink is specified in its spec: Example of a Kafka sink connected to an API server source apiVersion: sources.knative.dev/v1alpha2 kind: ApiServerSource metadata: name: <source-name> 1 namespace: <namespace> 2 spec: serviceAccountName: <service-account-name> 3 mode: Resource resources: - apiVersion: v1 kind: Event sink: ref: apiVersion: eventing.knative.dev/v1alpha1 kind: KafkaSink name: <sink-name> 4 1 The name of the event source. 2 The namespace of the event source. 3 The service account for the event source. 4 The Kafka sink name. 5.15.6. Additional resources Red Hat AMQ Streams documentation Red Hat AMQ Streams TLS and SASL on Kafka documentation Event delivery Knative Kafka cluster administrator documentation

Commands:
apiVersion: serving.knative.dev/v1 kind: Service metadata: name: hello 1 namespace: default 2 spec: template: spec: containers: - image: docker.io/openshift/hello-openshift 3 env: - name: RESPONSE 4 value: "Hello Serverless!"
kn service create <service-name> --image <image> --tag <tag-value>
kn service create event-display --image quay.io/openshift-knative/knative-eventing-sources-event-display:latest
Creating service 'event-display' in namespace 'default': 0.271s The Route is still working to reflect the latest desired specification. 0.580s Configuration "event-display" is waiting for a Revision to become ready. 3.857s 3.861s Ingress has not yet been reconciled. 4.270s Ready to serve. Service 'event-display' created with latest revision 'event-display-bxshg-1' and URL: http://event-display-default.apps-crc.testing
kn service create event-display --image quay.io/openshift-knative/knative-eventing-sources-event-display:latest --target ./ --namespace test
Service 'event-display' created in namespace 'test'.
tree ./
./ └── test └── ksvc └── event-display.yaml 2 directories, 1 file
cat test/ksvc/event-display.yaml
apiVersion: serving.knative.dev/v1 kind: Service metadata: creationTimestamp: null name: event-display namespace: test spec: template: metadata: annotations: client.knative.dev/user-image: quay.io/openshift-knative/knative-eventing-sources-event-display:latest creationTimestamp: null spec: containers: - image: quay.io/openshift-knative/knative-eventing-sources-event-display:latest name: "" resources: {} status: {}
kn service describe event-display --target ./ --namespace test
Name: event-display Namespace: test Age: URL: Revisions: Conditions: OK TYPE AGE REASON
kn service create -f test/ksvc/event-display.yaml
Creating service 'event-display' in namespace 'test': 0.058s The Route is still working to reflect the latest desired specification. 0.098s 0.168s Configuration "event-display" is waiting for a Revision to become ready. 23.377s 23.419s Ingress has not yet been reconciled. 23.534s Waiting for load balancer to be ready 23.723s Ready to serve. Service 'event-display' created to latest revision 'event-display-00001' is available at URL: http://event-display-test.apps.example.com
apiVersion: serving.knative.dev/v1 kind: Service metadata: name: event-delivery namespace: default spec: template: spec: containers: - image: quay.io/openshift-knative/knative-eventing-sources-event-display:latest env: - name: RESPONSE value: "Hello Serverless!"
oc apply -f <filename>
oc get ksvc <service_name>
NAME URL LATESTCREATED LATESTREADY READY REASON event-delivery http://event-delivery-default.example.com event-delivery-4wsd2 event-delivery-4wsd2 True
curl http://event-delivery-default.example.com
curl https://event-delivery-default.example.com
Hello Serverless!
curl https://event-delivery-default.example.com --insecure
Hello Serverless!
curl https://event-delivery-default.example.com --cacert <file>
Hello Serverless!
spec: ingress: kourier: service-type: LoadBalancer
oc -n knative-serving-ingress get svc kourier
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kourier LoadBalancer 172.30.51.103 a83e86291bcdd11e993af02b7a65e514-33544245.us-east-1.elb.amazonaws.com 80:31380/TCP,443:31390/TCP 67m
curl -H "Host: hello-default.example.com" a83e86291bcdd11e993af02b7a65e514-33544245.us-east-1.elb.amazonaws.com
Hello Serverless!
grpc.Dial( "a83e86291bcdd11e993af02b7a65e514-33544245.us-east-1.elb.amazonaws.com:80", grpc.WithAuthority("hello-default.example.com:80"), grpc.WithInsecure(), )
kind: NetworkPolicy apiVersion: networking.k8s.io/v1 metadata: name: deny-by-default namespace: example-namespace spec: podSelector: ingress: []
oc label namespace knative-serving knative.openshift.io/system-namespace=true
oc label namespace knative-serving-ingress knative.openshift.io/system-namespace=true
oc label namespace knative-eventing knative.openshift.io/system-namespace=true
oc label namespace knative-kafka knative.openshift.io/system-namespace=true
apiVersion: networking.k8s.io/v1 kind: NetworkPolicy metadata: name: <network_policy_name> 1 namespace: <namespace> 2 spec: ingress: - from: - namespaceSelector: matchLabels: knative.openshift.io/system-namespace: "true" podSelector: {} policyTypes: - Ingress
apiVersion: serving.knative.dev/v1 kind: Service spec: template: spec: initContainers: - imagePullPolicy: IfNotPresent 1 image: <image_uri> 2 volumeMounts: 3 - name: data mountPath: /data
apiVersion: serving.knative.dev/v1 kind: Service metadata: name: example namespace: default annotations: networking.knative.dev/http-option: "redirected" spec:
apiVersion: serving.knative.dev/v1 kind: Service metadata: name: example-service namespace: default spec: template: metadata: annotations: autoscaling.knative.dev/min-scale: "0"
kn service create <service_name> --image <image_uri> --scale-min <integer>
kn service create example-service --image quay.io/openshift-knative/knative-eventing-sources-event-display:latest --scale-min 2
apiVersion: serving.knative.dev/v1 kind: Service metadata: name: example-service namespace: default spec: template: metadata: annotations: autoscaling.knative.dev/max-scale: "10"
kn service create <service_name> --image <image_uri> --scale-max <integer>
kn service create example-service --image quay.io/openshift-knative/knative-eventing-sources-event-display:latest --scale-max 10
apiVersion: serving.knative.dev/v1 kind: Service metadata: name: example-service namespace: default spec: template: metadata: annotations: autoscaling.knative.dev/target: "200"
kn service create <service_name> --image <image_uri> --concurrency-target <integer>
kn service create example-service --image quay.io/openshift-knative/knative-eventing-sources-event-display:latest --concurrency-target 50
apiVersion: serving.knative.dev/v1 kind: Service metadata: name: example-service namespace: default spec: template: spec: containerConcurrency: 50
kn service create <service_name> --image <image_uri> --concurrency-limit <integer>
kn service create example-service --image quay.io/openshift-knative/knative-eventing-sources-event-display:latest --concurrency-limit 50
apiVersion: serving.knative.dev/v1 kind: Service metadata: name: example-service namespace: default spec: template: metadata: annotations: autoscaling.knative.dev/target-utilization-percentage: "70"
apiVersion: serving.knative.dev/v1 kind: Service metadata: name: example-service namespace: default spec: traffic: - latestRevision: true percent: 100 status: traffic: - percent: 100 revisionName: example-service
apiVersion: serving.knative.dev/v1 kind: Service metadata: name: example-service namespace: default spec: traffic: - tag: current revisionName: example-service percent: 100 - tag: latest latestRevision: true percent: 0
apiVersion: serving.knative.dev/v1 kind: Service metadata: name: example-service namespace: default spec: traffic: - tag: current revisionName: example-service-1 percent: 50 - tag: candidate revisionName: example-service-2 percent: 50 - tag: latest latestRevision: true percent: 0
kn service update <service_name> --tag @latest=example-tag
kn service update <service_name> --untag example-tag
kn service update <service_name> --traffic <revision>=<percentage>
kn service update example-service --traffic @latest=20,stable=80
kn service update example-service --traffic @latest=10,stable=60
oc get ksvc <service_name> -o=jsonpath='{.status.latestCreatedRevisionName}'
oc get ksvc example-service -o=jsonpath='{.status.latestCreatedRevisionName}'
example-service-00001
spec: traffic: - revisionName: <first_revision_name> percent: 100 # All traffic goes to this revision
oc get ksvc <service_name>
oc get ksvc <service_name> -o=jsonpath='{.status.latestCreatedRevisionName}'
spec: traffic: - revisionName: <first_revision_name> percent: 100 # All traffic is still being routed to the first revision - revisionName: <second_revision_name> percent: 0 # No traffic is routed to the second revision tag: v2 # A named route
oc get ksvc <service_name> --output jsonpath="{.status.traffic[*].url}"
spec: traffic: - revisionName: <first_revision_name> percent: 50 - revisionName: <second_revision_name> percent: 50 tag: v2
spec: traffic: - revisionName: <first_revision_name> percent: 0 - revisionName: <second_revision_name> percent: 100 tag: v2
apiVersion: serving.knative.dev/v1 kind: Service metadata: name: <service_name> labels: <label_name>: <label_value> annotations: <annotation_name>: <annotation_value>
kn service create <service_name> --image=<image> --annotation <annotation_name>=<annotation_value> --label <label_value>=<label_value>
oc get routes.route.openshift.io -l serving.knative.openshift.io/ingressName=<service_name> \ 1 -l serving.knative.openshift.io/ingressNamespace=<service_namespace> \ 2 -n knative-serving-ingress -o yaml | grep -e "<label_name>: \"<label_value>\"" -e "<annotation_name>: <annotation_value>" 3
apiVersion: serving.knative.dev/v1 kind: Service metadata: name: <service_name> annotations: serving.knative.openshift.io/disableRoute: "true" spec: template: spec: containers: - image: <image>
oc apply -f <filename>
kn service create <service_name> --image=gcr.io/knative-samples/helloworld-go --annotation serving.knative.openshift.io/disableRoute=true
USD oc get routes.route.openshift.io -l serving.knative.openshift.io/ingressName=USDKSERVICE_NAME -l serving.knative.openshift.io/ingressNamespace=USDKSERVICE_NAMESPACE -n knative-serving-ingress
No resources found in knative-serving-ingress namespace.
apiVersion: route.openshift.io/v1 kind: Route metadata: annotations: haproxy.router.openshift.io/timeout: 600s 1 name: <route_name> 2 namespace: knative-serving-ingress 3 spec: host: <service_host> 4 port: targetPort: http2 to: kind: Service name: kourier weight: 100 tls: insecureEdgeTerminationPolicy: Allow termination: edge 5 key: |- -----BEGIN PRIVATE KEY----- [...] -----END PRIVATE KEY----- certificate: |- -----BEGIN CERTIFICATE----- [...] -----END CERTIFICATE----- caCertificate: |- -----BEGIN CERTIFICATE----- [...] -----END CERTIFICATE---- wildcardPolicy: None
oc apply -f <filename>
oc label ksvc <service_name> networking.knative.dev/visibility=cluster-local
oc get ksvc
NAME URL LATESTCREATED LATESTREADY READY REASON hello http://hello.default.svc.cluster.local hello-tx2g7 hello-tx2g7 True
kn source binding create bind-heartbeat --namespace sinkbinding-example --subject "Job:batch/v1:app=heartbeat-cron" --sink http://event-display.svc.cluster.local \ 1 --ce-override "sink=bound"
apiVersion: eventing.knative.dev/v1 kind: Trigger metadata: name: <trigger_name> 1 spec: subscriber: ref: apiVersion: eventing.knative.dev/v1alpha1 kind: KafkaSink name: <kafka_sink_name> 2
apiVersion: eventing.knative.dev/v1 kind: Broker metadata: spec: delivery: deadLetterSink: ref: apiVersion: eventing.knative.dev/v1alpha1 kind: KafkaSink name: <sink_name> backoffDelay: <duration> backoffPolicy: <policy_type> retry: <integer>
apiVersion: eventing.knative.dev/v1 kind: Trigger metadata: spec: broker: <broker_name> delivery: deadLetterSink: ref: apiVersion: serving.knative.dev/v1 kind: Service name: <sink_name> backoffDelay: <duration> backoffPolicy: <policy_type> retry: <integer>
apiVersion: messaging.knative.dev/v1 kind: Channel metadata: spec: delivery: deadLetterSink: ref: apiVersion: serving.knative.dev/v1 kind: Service name: <sink_name> backoffDelay: <duration> backoffPolicy: <policy_type> retry: <integer>
apiVersion: messaging.knative.dev/v1 kind: Subscription metadata: spec: channel: apiVersion: messaging.knative.dev/v1 kind: Channel name: <channel_name> delivery: deadLetterSink: ref: apiVersion: serving.knative.dev/v1 kind: Service name: <sink_name> backoffDelay: <duration> backoffPolicy: <policy_type> retry: <integer>
apiVersion: eventing.knative.dev/v1 kind: Trigger metadata: name: <trigger_name> annotations: kafka.eventing.knative.dev/delivery.order: ordered
oc apply -f <filename>
kn source list-types
TYPE NAME DESCRIPTION ApiServerSource apiserversources.sources.knative.dev Watch and send Kubernetes API events to a sink PingSource pingsources.sources.knative.dev Periodically send ping events to a sink SinkBinding sinkbindings.sources.knative.dev Binding for connecting a PodSpecable to a sink
kn source list-types -o yaml
kn source list
NAME TYPE RESOURCE SINK READY a1 ApiServerSource apiserversources.sources.knative.dev ksvc:eshow2 True b1 SinkBinding sinkbindings.sources.knative.dev ksvc:eshow3 False p1 PingSource pingsources.sources.knative.dev ksvc:eshow1 True
kn source list --type <event_source_type>
kn source list --type PingSource
NAME TYPE RESOURCE SINK READY p1 PingSource pingsources.sources.knative.dev ksvc:eshow1 True
apiVersion: v1 kind: ServiceAccount metadata: name: events-sa namespace: default 1 --- apiVersion: rbac.authorization.k8s.io/v1 kind: Role metadata: name: event-watcher namespace: default 2 rules: - apiGroups: - "" resources: - events verbs: - get - list - watch --- apiVersion: rbac.authorization.k8s.io/v1 kind: RoleBinding metadata: name: k8s-ra-event-watcher namespace: default 3 roleRef: apiGroup: rbac.authorization.k8s.io kind: Role name: event-watcher subjects: - kind: ServiceAccount name: events-sa namespace: default 4
oc apply -f <filename>
apiVersion: v1 kind: ServiceAccount metadata: name: events-sa namespace: default 1 --- apiVersion: rbac.authorization.k8s.io/v1 kind: Role metadata: name: event-watcher namespace: default 2 rules: - apiGroups: - "" resources: - events verbs: - get - list - watch --- apiVersion: rbac.authorization.k8s.io/v1 kind: RoleBinding metadata: name: k8s-ra-event-watcher namespace: default 3 roleRef: apiGroup: rbac.authorization.k8s.io kind: Role name: event-watcher subjects: - kind: ServiceAccount name: events-sa namespace: default 4
oc apply -f <filename>
kn source apiserver create <event_source_name> --sink broker:<broker_name> --resource "event:v1" --service-account <service_account_name> --mode Resource
kn service create <service_name> --image quay.io/openshift-knative/knative-eventing-sources-event-display:latest
kn trigger create <trigger_name> --sink ksvc:<service_name>
oc create deployment hello-node --image quay.io/openshift-knative/knative-eventing-sources-event-display:latest
kn source apiserver describe <source_name>
Name: mysource Namespace: default Annotations: sources.knative.dev/creator=developer, sources.knative.dev/lastModifier=developer Age: 3m ServiceAccountName: events-sa Mode: Resource Sink: Name: default Namespace: default Kind: Broker (eventing.knative.dev/v1) Resources: Kind: event (v1) Controller: false Conditions: OK TYPE AGE REASON ++ Ready 3m ++ Deployed 3m ++ SinkProvided 3m ++ SufficientPermissions 3m ++ EventTypesProvided 3m
oc get pods
oc logs USD(oc get pod -o name | grep event-display) -c user-container
☁\ufe0f cloudevents.Event Validation: valid Context Attributes, specversion: 1.0 type: dev.knative.apiserver.resource.update datacontenttype: application/json Data, { "apiVersion": "v1", "involvedObject": { "apiVersion": "v1", "fieldPath": "spec.containers{hello-node}", "kind": "Pod", "name": "hello-node", "namespace": "default", .. }, "kind": "Event", "message": "Started container", "metadata": { "name": "hello-node.159d7608e3a3572c", "namespace": "default", . }, "reason": "Started", }
kn trigger delete <trigger_name>
kn source apiserver delete <source_name>
oc delete -f authentication.yaml
kn source binding create bind-heartbeat --namespace sinkbinding-example --subject "Job:batch/v1:app=heartbeat-cron" --sink http://event-display.svc.cluster.local \ 1 --ce-override "sink=bound"
apiVersion: v1 kind: ServiceAccount metadata: name: events-sa namespace: default 1 --- apiVersion: rbac.authorization.k8s.io/v1 kind: Role metadata: name: event-watcher namespace: default 2 rules: - apiGroups: - "" resources: - events verbs: - get - list - watch --- apiVersion: rbac.authorization.k8s.io/v1 kind: RoleBinding metadata: name: k8s-ra-event-watcher namespace: default 3 roleRef: apiGroup: rbac.authorization.k8s.io kind: Role name: event-watcher subjects: - kind: ServiceAccount name: events-sa namespace: default 4
oc apply -f <filename>
apiVersion: sources.knative.dev/v1alpha1 kind: ApiServerSource metadata: name: testevents spec: serviceAccountName: events-sa mode: Resource resources: - apiVersion: v1 kind: Event sink: ref: apiVersion: eventing.knative.dev/v1 kind: Broker name: default
oc apply -f <filename>
apiVersion: serving.knative.dev/v1 kind: Service metadata: name: event-display namespace: default spec: template: spec: containers: - image: quay.io/openshift-knative/knative-eventing-sources-event-display:latest
oc apply -f <filename>
apiVersion: eventing.knative.dev/v1 kind: Trigger metadata: name: event-display-trigger namespace: default spec: broker: default subscriber: ref: apiVersion: serving.knative.dev/v1 kind: Service name: event-display
oc apply -f <filename>
oc create deployment hello-node --image=quay.io/openshift-knative/knative-eventing-sources-event-display
oc get apiserversource.sources.knative.dev testevents -o yaml
apiVersion: sources.knative.dev/v1alpha1 kind: ApiServerSource metadata: annotations: creationTimestamp: "2020-04-07T17:24:54Z" generation: 1 name: testevents namespace: default resourceVersion: "62868" selfLink: /apis/sources.knative.dev/v1alpha1/namespaces/default/apiserversources/testevents2 uid: 1603d863-bb06-4d1c-b371-f580b4db99fa spec: mode: Resource resources: - apiVersion: v1 controller: false controllerSelector: apiVersion: "" kind: "" name: "" uid: "" kind: Event labelSelector: {} serviceAccountName: events-sa sink: ref: apiVersion: eventing.knative.dev/v1 kind: Broker name: default
oc get pods
oc logs USD(oc get pod -o name | grep event-display) -c user-container
☁\ufe0f cloudevents.Event Validation: valid Context Attributes, specversion: 1.0 type: dev.knative.apiserver.resource.update datacontenttype: application/json Data, { "apiVersion": "v1", "involvedObject": { "apiVersion": "v1", "fieldPath": "spec.containers{hello-node}", "kind": "Pod", "name": "hello-node", "namespace": "default", .. }, "kind": "Event", "message": "Started container", "metadata": { "name": "hello-node.159d7608e3a3572c", "namespace": "default", . }, "reason": "Started", }
oc delete -f trigger.yaml
oc delete -f k8s-events.yaml
oc delete -f authentication.yaml
apiVersion: serving.knative.dev/v1 kind: Service metadata: name: event-display spec: template: spec: containers: - image: quay.io/openshift-knative/knative-eventing-sources-event-display:latest
kn service create event-display --image quay.io/openshift-knative/knative-eventing-sources-event-display:latest
kn source ping create test-ping-source --schedule "*/2 * * * *" --data '{"message": "Hello world!"}' --sink ksvc:event-display
kn source ping describe test-ping-source
Name: test-ping-source Namespace: default Annotations: sources.knative.dev/creator=developer, sources.knative.dev/lastModifier=developer Age: 15s Schedule: */2 * * * * Data: {"message": "Hello world!"} Sink: Name: event-display Namespace: default Resource: Service (serving.knative.dev/v1) Conditions: OK TYPE AGE REASON ++ Ready 8s ++ Deployed 8s ++ SinkProvided 15s ++ ValidSchedule 15s ++ EventTypeProvided 15s ++ ResourcesCorrect 15s
watch oc get pods
oc logs USD(oc get pod -o name | grep event-display) -c user-container
☁\ufe0f cloudevents.Event Validation: valid Context Attributes, specversion: 1.0 type: dev.knative.sources.ping source: /apis/v1/namespaces/default/pingsources/test-ping-source id: 99e4f4f6-08ff-4bff-acf1-47f61ded68c9 time: 2020-04-07T16:16:00.000601161Z datacontenttype: application/json Data, { "message": "Hello world!" }
kn delete pingsources.sources.knative.dev <ping_source_name>
kn source binding create bind-heartbeat --namespace sinkbinding-example --subject "Job:batch/v1:app=heartbeat-cron" --sink http://event-display.svc.cluster.local \ 1 --ce-override "sink=bound"
apiVersion: sources.knative.dev/v1 kind: PingSource metadata: name: test-ping-source spec: schedule: "*/2 * * * *" 1 data: '{"message": "Hello world!"}' 2 sink: 3 ref: apiVersion: serving.knative.dev/v1 kind: Service name: event-display
apiVersion: serving.knative.dev/v1 kind: Service metadata: name: event-display spec: template: spec: containers: - image: quay.io/openshift-knative/knative-eventing-sources-event-display:latest
oc apply -f <filename>
apiVersion: sources.knative.dev/v1 kind: PingSource metadata: name: test-ping-source spec: schedule: "*/2 * * * *" data: '{"message": "Hello world!"}' sink: ref: apiVersion: serving.knative.dev/v1 kind: Service name: event-display
oc apply -f <filename>
oc get pingsource.sources.knative.dev <ping_source_name> -oyaml
apiVersion: sources.knative.dev/v1 kind: PingSource metadata: annotations: sources.knative.dev/creator: developer sources.knative.dev/lastModifier: developer creationTimestamp: "2020-04-07T16:11:14Z" generation: 1 name: test-ping-source namespace: default resourceVersion: "55257" selfLink: /apis/sources.knative.dev/v1/namespaces/default/pingsources/test-ping-source uid: 3d80d50b-f8c7-4c1b-99f7-3ec00e0a8164 spec: data: '{ value: "hello" }' schedule: '*/2 * * * *' sink: ref: apiVersion: serving.knative.dev/v1 kind: Service name: event-display namespace: default
watch oc get pods
oc logs USD(oc get pod -o name | grep event-display) -c user-container
☁\ufe0f cloudevents.Event Validation: valid Context Attributes, specversion: 1.0 type: dev.knative.sources.ping source: /apis/v1/namespaces/default/pingsources/test-ping-source id: 042ff529-240e-45ee-b40c-3a908129853e time: 2020-04-07T16:22:00.000791674Z datacontenttype: application/json Data, { "message": "Hello world!" }
oc delete -f <filename>
oc delete -f ping-source.yaml
apiVersion: serving.knative.dev/v1 kind: Service metadata: name: event-display spec: template: spec: containers: - image: quay.io/openshift-knative/knative-eventing-sources-event-display:latest
oc apply -f <filename>
apiVersion: sources.knative.dev/v1alpha1 kind: SinkBinding metadata: name: bind-heartbeat spec: subject: apiVersion: batch/v1 kind: Job 1 selector: matchLabels: app: heartbeat-cron sink: ref: apiVersion: serving.knative.dev/v1 kind: Service name: event-display
oc apply -f <filename>
apiVersion: batch/v1beta1 kind: CronJob metadata: name: heartbeat-cron spec: # Run every minute schedule: "* * * * *" jobTemplate: metadata: labels: app: heartbeat-cron bindings.knative.dev/include: "true" spec: template: spec: restartPolicy: Never containers: - name: single-heartbeat image: quay.io/openshift-knative/heartbeats:latest args: - --period=1 env: - name: ONE_SHOT value: "true" - name: POD_NAME valueFrom: fieldRef: fieldPath: metadata.name - name: POD_NAMESPACE valueFrom: fieldRef: fieldPath: metadata.namespace
jobTemplate: metadata: labels: app: heartbeat-cron bindings.knative.dev/include: "true"
oc apply -f <filename>
oc get sinkbindings.sources.knative.dev bind-heartbeat -oyaml
spec: sink: ref: apiVersion: serving.knative.dev/v1 kind: Service name: event-display namespace: default subject: apiVersion: batch/v1 kind: Job namespace: default selector: matchLabels: app: heartbeat-cron
oc get pods
oc logs USD(oc get pod -o name | grep event-display) -c user-container
☁\ufe0f cloudevents.Event Validation: valid Context Attributes, specversion: 1.0 type: dev.knative.eventing.samples.heartbeat source: https://knative.dev/eventing-contrib/cmd/heartbeats/#event-test/mypod id: 2b72d7bf-c38f-4a98-a433-608fbcdd2596 time: 2019-10-18T15:23:20.809775386Z contenttype: application/json Extensions, beats: true heart: yes the: 42 Data, { "id": 1, "label": "" }
kn service create event-display --image quay.io/openshift-knative/knative-eventing-sources-event-display:latest
kn source binding create bind-heartbeat --subject Job:batch/v1:app=heartbeat-cron --sink ksvc:event-display
apiVersion: batch/v1beta1 kind: CronJob metadata: name: heartbeat-cron spec: # Run every minute schedule: "* * * * *" jobTemplate: metadata: labels: app: heartbeat-cron bindings.knative.dev/include: "true" spec: template: spec: restartPolicy: Never containers: - name: single-heartbeat image: quay.io/openshift-knative/heartbeats:latest args: - --period=1 env: - name: ONE_SHOT value: "true" - name: POD_NAME valueFrom: fieldRef: fieldPath: metadata.name - name: POD_NAMESPACE valueFrom: fieldRef: fieldPath: metadata.namespace
jobTemplate: metadata: labels: app: heartbeat-cron bindings.knative.dev/include: "true"
oc apply -f <filename>
kn source binding describe bind-heartbeat
Name: bind-heartbeat Namespace: demo-2 Annotations: sources.knative.dev/creator=minikube-user, sources.knative.dev/lastModifier=minikub Age: 2m Subject: Resource: job (batch/v1) Selector: app: heartbeat-cron Sink: Name: event-display Resource: Service (serving.knative.dev/v1) Conditions: OK TYPE AGE REASON ++ Ready 2m
oc get pods
oc logs USD(oc get pod -o name | grep event-display) -c user-container
☁\ufe0f cloudevents.Event Validation: valid Context Attributes, specversion: 1.0 type: dev.knative.eventing.samples.heartbeat source: https://knative.dev/eventing-contrib/cmd/heartbeats/#event-test/mypod id: 2b72d7bf-c38f-4a98-a433-608fbcdd2596 time: 2019-10-18T15:23:20.809775386Z contenttype: application/json Extensions, beats: true heart: yes the: 42 Data, { "id": 1, "label": "" }
kn source binding create bind-heartbeat --namespace sinkbinding-example --subject "Job:batch/v1:app=heartbeat-cron" --sink http://event-display.svc.cluster.local \ 1 --ce-override "sink=bound"
apiVersion: serving.knative.dev/v1 kind: Service metadata: name: event-display spec: template: spec: containers: - image: quay.io/openshift-knative/knative-eventing-sources-event-display:latest
apiVersion: batch/v1 kind: CronJob metadata: name: heartbeat-cron spec: # Run every minute schedule: "*/1 * * * *" jobTemplate: metadata: labels: app: heartbeat-cron bindings.knative.dev/include: true 1 spec: template: spec: restartPolicy: Never containers: - name: single-heartbeat image: quay.io/openshift-knative/heartbeats args: - --period=1 env: - name: ONE_SHOT value: "true" - name: POD_NAME valueFrom: fieldRef: fieldPath: metadata.name - name: POD_NAMESPACE valueFrom: fieldRef: fieldPath: metadata.namespace
apiVersion: sources.knative.dev/v1 kind: SinkBinding metadata: name: bind-heartbeat spec: subject: apiVersion: apps/v1 kind: Deployment namespace: default name: mysubject
apiVersion: sources.knative.dev/v1 kind: SinkBinding metadata: name: bind-heartbeat spec: subject: apiVersion: batch/v1 kind: Job namespace: default selector: matchLabels: working: example
apiVersion: sources.knative.dev/v1 kind: SinkBinding metadata: name: bind-heartbeat spec: subject: apiVersion: v1 kind: Pod namespace: default selector: - matchExpression: key: working operator: In values: - example - sample
apiVersion: sources.knative.dev/v1 kind: SinkBinding metadata: name: bind-heartbeat spec: ceOverrides: extensions: extra: this is an extra attribute additional: 42
{ "extensions": { "extra": "this is an extra attribute", "additional": "42" } }
oc label namespace <namespace> bindings.knative.dev/include=true
package main import ( "context" "encoding/json" "flag" "fmt" "log" "os" "strconv" "time" duckv1 "knative.dev/pkg/apis/duck/v1" cloudevents "github.com/cloudevents/sdk-go/v2" "github.com/kelseyhightower/envconfig" ) type Heartbeat struct { Sequence int `json:"id"` Label string `json:"label"` } var ( eventSource string eventType string sink string label string periodStr string ) func init() { flag.StringVar(&eventSource, "eventSource", "", "the event-source (CloudEvents)") flag.StringVar(&eventType, "eventType", "dev.knative.eventing.samples.heartbeat", "the event-type (CloudEvents)") flag.StringVar(&sink, "sink", "", "the host url to heartbeat to") flag.StringVar(&label, "label", "", "a special label") flag.StringVar(&periodStr, "period", "5", "the number of seconds between heartbeats") } type envConfig struct { // Sink URL where to send heartbeat cloud events Sink string `envconfig:"K_SINK"` // CEOverrides are the CloudEvents overrides to be applied to the outbound event. CEOverrides string `envconfig:"K_CE_OVERRIDES"` // Name of this pod. Name string `envconfig:"POD_NAME" required:"true"` // Namespace this pod exists in. Namespace string `envconfig:"POD_NAMESPACE" required:"true"` // Whether to run continuously or exit. OneShot bool `envconfig:"ONE_SHOT" default:"false"` } func main() { flag.Parse() var env envConfig if err := envconfig.Process("", &env); err != nil { log.Printf("[ERROR] Failed to process env var: %s", err) os.Exit(1) } if env.Sink != "" { sink = env.Sink } var ceOverrides *duckv1.CloudEventOverrides if len(env.CEOverrides) > 0 { overrides := duckv1.CloudEventOverrides{} err := json.Unmarshal([]byte(env.CEOverrides), &overrides) if err != nil { log.Printf("[ERROR] Unparseable CloudEvents overrides %s: %v", env.CEOverrides, err) os.Exit(1) } ceOverrides = &overrides } p, err := cloudevents.NewHTTP(cloudevents.WithTarget(sink)) if err != nil { log.Fatalf("failed to create http protocol: %s", err.Error()) } c, err := cloudevents.NewClient(p, cloudevents.WithUUIDs(), cloudevents.WithTimeNow()) if err != nil { log.Fatalf("failed to create client: %s", err.Error()) } var period time.Duration if p, err := strconv.Atoi(periodStr); err != nil { period = time.Duration(5) * time.Second } else { period = time.Duration(p) * time.Second } if eventSource == "" { eventSource = fmt.Sprintf("https://knative.dev/eventing-contrib/cmd/heartbeats/#%s/%s", env.Namespace, env.Name) log.Printf("Heartbeats Source: %s", eventSource) } if len(label) > 0 && label[0] == '"' { label, _ = strconv.Unquote(label) } hb := &Heartbeat{ Sequence: 0, Label: label, } ticker := time.NewTicker(period) for { hb.Sequence++ event := cloudevents.NewEvent("1.0") event.SetType(eventType) event.SetSource(eventSource) event.SetExtension("the", 42) event.SetExtension("heart", "yes") event.SetExtension("beats", true) if ceOverrides != nil && ceOverrides.Extensions != nil { for n, v := range ceOverrides.Extensions { event.SetExtension(n, v) } } if err := event.SetData(cloudevents.ApplicationJSON, hb); err != nil { log.Printf("failed to set cloudevents data: %s", err.Error()) } log.Printf("sending cloudevent to %s", sink) if res := c.Send(context.Background(), event); !cloudevents.IsACK(res) { log.Printf("failed to send cloudevent: %v", res) } if env.OneShot { return } // Wait for next tick <-ticker.C } }
apiVersion: sources.knative.dev/v1 kind: ContainerSource metadata: name: test-heartbeats spec: template: spec: containers: # This corresponds to a heartbeats image URI that you have built and published - image: gcr.io/knative-releases/knative.dev/eventing/cmd/heartbeats name: heartbeats args: - --period=1 env: - name: POD_NAME value: "example-pod" - name: POD_NAMESPACE value: "event-test" sink: ref: apiVersion: serving.knative.dev/v1 kind: Service name: example-service
kn source container create <container_source_name> --image <image_uri> --sink <sink>
kn source container delete <container_source_name>
kn source container describe <container_source_name>
kn source container list
kn source container list -o yaml
kn source container update <container_source_name> --image <image_uri>
apiVersion: sources.knative.dev/v1 kind: ContainerSource metadata: name: test-heartbeats spec: template: spec: containers: - image: quay.io/openshift-knative/heartbeats:latest name: heartbeats args: - --period=1 env: - name: POD_NAME value: "mypod" - name: POD_NAMESPACE value: "event-test"
apiVersion: sources.knative.dev/v1 kind: ContainerSource metadata: name: test-heartbeats spec: ceOverrides: extensions: extra: this is an extra attribute additional: 42
{ "extensions": { "extra": "this is an extra attribute", "additional": "42" } }
kn channel create <channel_name> --type <channel_type>
kn channel create mychannel --type messaging.knative.dev:v1:InMemoryChannel
Channel 'mychannel' created in namespace 'default'.
kn channel list
kn channel list NAME TYPE URL AGE READY REASON mychannel InMemoryChannel http://mychannel-kn-channel.default.svc.cluster.local 93s True
kn channel delete <channel_name>
apiVersion: messaging.knative.dev/v1 kind: Channel metadata: name: example-channel namespace: default
oc apply -f <filename>
apiVersion: messaging.knative.dev/v1beta1 kind: KafkaChannel metadata: name: example-channel namespace: default spec: numPartitions: 3 replicationFactor: 1
oc apply -f <filename>
apiVersion: messaging.knative.dev/v1beta1 kind: Subscription metadata: name: my-subscription 1 namespace: default spec: channel: 2 apiVersion: messaging.knative.dev/v1beta1 kind: Channel name: example-channel delivery: 3 deadLetterSink: ref: apiVersion: serving.knative.dev/v1 kind: Service name: error-handler subscriber: 4 ref: apiVersion: serving.knative.dev/v1 kind: Service name: event-display
oc apply -f <filename>
kn subscription create <subscription_name> --channel <group:version:kind>:<channel_name> \ 1 --sink <sink_prefix>:<sink_name> \ 2 --sink-dead-letter <sink_prefix>:<sink_name> 3
kn subscription create mysubscription --channel mychannel --sink ksvc:event-display
Subscription 'mysubscription' created in namespace 'default'.
kn subscription list
NAME CHANNEL SUBSCRIBER REPLY DEAD LETTER SINK READY REASON mysubscription Channel:mychannel ksvc:event-display True
kn subscription delete <subscription_name>
kn subscription describe <subscription_name>
Name: my-subscription Namespace: default Annotations: messaging.knative.dev/creator=openshift-user, messaging.knative.dev/lastModifier=min Age: 43s Channel: Channel:my-channel (messaging.knative.dev/v1) Subscriber: URI: http://edisplay.default.example.com Reply: Name: default Resource: Broker (eventing.knative.dev/v1) DeadLetterSink: Name: my-sink Resource: Service (serving.knative.dev/v1) Conditions: OK TYPE AGE REASON ++ Ready 43s ++ AddedToChannel 43s ++ ChannelReady 43s ++ ReferencesResolved 43s
kn subscription list
NAME CHANNEL SUBSCRIBER REPLY DEAD LETTER SINK READY REASON mysubscription Channel:mychannel ksvc:event-display True
kn subscription update <subscription_name> --sink <sink_prefix>:<sink_name> \ 1 --sink-dead-letter <sink_prefix>:<sink_name> 2
kn subscription update mysubscription --sink ksvc:event-display
kn broker create <broker_name>
kn broker list
NAME URL AGE CONDITIONS READY REASON default http://broker-ingress.knative-eventing.svc.cluster.local/test/default 45s 5 OK / 5 True
apiVersion: eventing.knative.dev/v1 kind: Trigger metadata: annotations: eventing.knative.dev/injection: enabled name: <trigger_name> spec: broker: default subscriber: 1 ref: apiVersion: serving.knative.dev/v1 kind: Service name: <service_name>
oc apply -f <filename>
oc -n <namespace> get broker default
NAME READY REASON URL AGE default True http://broker-ingress.knative-eventing.svc.cluster.local/test/default 3m56s
oc label namespace <namespace> eventing.knative.dev/injection=enabled
oc -n <namespace> get broker <broker_name>
oc -n default get broker default
NAME READY REASON URL AGE default True http://broker-ingress.knative-eventing.svc.cluster.local/test/default 3m56s
oc label namespace <namespace> eventing.knative.dev/injection-
oc -n <namespace> delete broker <broker_name>
oc -n <namespace> get broker <broker_name>
oc -n default get broker default
No resources found. Error from server (NotFound): brokers.eventing.knative.dev "default" not found
apiVersion: eventing.knative.dev/v1 kind: Broker metadata: annotations: eventing.knative.dev/broker.class: Kafka 1 name: example-kafka-broker spec: config: apiVersion: v1 kind: ConfigMap name: kafka-broker-config 2 namespace: knative-eventing
oc apply -f <filename>
apiVersion: eventing.knative.dev/v1 kind: Broker metadata: annotations: eventing.knative.dev/broker.class: Kafka 1 kafka.eventing.knative.dev/external.topic: <topic_name> 2
oc apply -f <filename>
kn broker list
NAME URL AGE CONDITIONS READY REASON default http://broker-ingress.knative-eventing.svc.cluster.local/test/default 45s 5 OK / 5 True
kn broker describe <broker_name>
kn broker describe default
Name: default Namespace: default Annotations: eventing.knative.dev/broker.class=MTChannelBasedBroker, eventing.knative.dev/creato Age: 22s Address: URL: http://broker-ingress.knative-eventing.svc.cluster.local/default/default Conditions: OK TYPE AGE REASON ++ Ready 22s ++ Addressable 22s ++ FilterReady 22s ++ IngressReady 22s ++ TriggerChannelReady 22s
kn trigger create <trigger_name> --broker <broker_name> --filter <key=value> --sink <sink_name>
kn trigger create <trigger_name> --inject-broker --filter <key=value> --sink <sink_name>
kn trigger list
NAME BROKER SINK AGE CONDITIONS READY REASON email default ksvc:edisplay 4s 5 OK / 5 True ping default ksvc:edisplay 32s 5 OK / 5 True
kn trigger list -o json
kn trigger describe <trigger_name>
Name: ping Namespace: default Labels: eventing.knative.dev/broker=default Annotations: eventing.knative.dev/creator=kube:admin, eventing.knative.dev/lastModifier=kube:admin Age: 2m Broker: default Filter: type: dev.knative.event Sink: Name: edisplay Namespace: default Resource: Service (serving.knative.dev/v1) Conditions: OK TYPE AGE REASON ++ Ready 2m ++ BrokerReady 2m ++ DependencyReady 2m ++ Subscribed 2m ++ SubscriberResolved 2m
kn trigger create <trigger_name> --broker <broker_name> --filter type=dev.knative.samples.helloworld --sink ksvc:<service_name>
kn trigger create <trigger_name> --broker <broker_name> --sink ksvc:<service_name> --filter type=dev.knative.samples.helloworld --filter source=dev.knative.samples/helloworldsource --filter myextension=my-extension-value
kn trigger update <trigger_name> --filter <key=value> --sink <sink_name> [flags]
kn trigger update <trigger_name> --filter type=knative.dev.event
kn trigger update <trigger_name> --filter type-
kn trigger update <trigger_name> --sink ksvc:my-event-sink
kn trigger delete <trigger_name>
kn trigger list
No triggers found.
apiVersion: eventing.knative.dev/v1 kind: Trigger metadata: name: <trigger_name> annotations: kafka.eventing.knative.dev/delivery.order: ordered
oc apply -f <filename>
kn service create event-display --image quay.io/openshift-knative/knative-eventing-sources-event-display
kn source kafka create <kafka_source_name> --servers <cluster_kafka_bootstrap>.kafka.svc:9092 --topics <topic_name> --consumergroup my-consumer-group --sink event-display
kn source kafka describe <kafka_source_name>
Name: example-kafka-source Namespace: kafka Age: 1h BootstrapServers: example-cluster-kafka-bootstrap.kafka.svc:9092 Topics: example-topic ConsumerGroup: example-consumer-group Sink: Name: event-display Namespace: default Resource: Service (serving.knative.dev/v1) Conditions: OK TYPE AGE REASON ++ Ready 1h ++ Deployed 1h ++ SinkProvided 1h
oc -n kafka run kafka-producer -ti --image=quay.io/strimzi/kafka:latest-kafka-2.7.0 --rm=true --restart=Never -- bin/kafka-console-producer.sh --broker-list <cluster_kafka_bootstrap>:9092 --topic my-topic
oc logs USD(oc get pod -o name | grep event-display) -c user-container
☁\ufe0f cloudevents.Event Validation: valid Context Attributes, specversion: 1.0 type: dev.knative.kafka.event source: /apis/v1/namespaces/default/kafkasources/example-kafka-source#example-topic subject: partition:46#0 id: partition:46/offset:0 time: 2021-03-10T11:21:49.4Z Extensions, traceparent: 00-161ff3815727d8755848ec01c866d1cd-7ff3916c44334678-00 Data, Hello!
kn source binding create bind-heartbeat --namespace sinkbinding-example --subject "Job:batch/v1:app=heartbeat-cron" --sink http://event-display.svc.cluster.local \ 1 --ce-override "sink=bound"
apiVersion: sources.knative.dev/v1beta1 kind: KafkaSource metadata: name: <source_name> spec: consumerGroup: <group_name> 1 bootstrapServers: - <list_of_bootstrap_servers> topics: - <list_of_topics> 2 sink: - <list_of_sinks> 3
apiVersion: sources.knative.dev/v1beta1 kind: KafkaSource metadata: name: kafka-source spec: consumerGroup: knative-group bootstrapServers: - my-cluster-kafka-bootstrap.kafka:9092 topics: - knative-demo-topic sink: ref: apiVersion: serving.knative.dev/v1 kind: Service name: event-display
oc apply -f <filename>
oc get pods
NAME READY STATUS RESTARTS AGE kafkasource-kafka-source-5ca0248f-... 1/1 Running 0 13m
apiVersion: messaging.knative.dev/v1beta1 kind: KafkaChannel metadata: name: example-channel namespace: default spec: numPartitions: 3 replicationFactor: 1
oc apply -f <filename>
apiVersion: eventing.knative.dev/v1alpha1 kind: KafkaSink metadata: name: <sink-name> namespace: <namespace> spec: topic: <topic-name> bootstrapServers: - <bootstrap-server>
oc apply -f <filename>
apiVersion: sources.knative.dev/v1alpha2 kind: ApiServerSource metadata: name: <source-name> 1 namespace: <namespace> 2 spec: serviceAccountName: <service-account-name> 3 mode: Resource resources: - apiVersion: v1 kind: Event sink: ref: apiVersion: eventing.knative.dev/v1alpha1 kind: KafkaSink name: <sink-name> 4