Chapter 5. Eventing 5.1. Knative Eventing Knative Eventing on OpenShift Container Platform enables developers to use an event-driven architecture with serverless applications. An event-driven architecture is based on the concept of decoupled relationships between event producers and event consumers. Event producers create events, and event sinks , or consumers, receive events. Knative Eventing uses standard HTTP POST requests to send and receive events between event producers and sinks. These events conform to the CloudEvents specifications , which enables creating, parsing, sending, and receiving events in any programming language. Knative Eventing supports the following use cases: Publish an event without creating a consumer You can send events to a broker as an HTTP POST, and use binding to decouple the destination configuration from your application that produces events. Consume an event without creating a publisher You can use a trigger to consume events from a broker based on event attributes. The application receives events as an HTTP POST. To enable delivery to multiple types of sinks, Knative Eventing defines the following generic interfaces that can be implemented by multiple Kubernetes resources: Addressable resources Able to receive and acknowledge an event delivered over HTTP to an address defined in the status.address.url field of the event. The Kubernetes Service resource also satisfies the addressable interface. Callable resources Able to receive an event delivered over HTTP and transform it, returning 0 or 1 new events in the HTTP response payload. These returned events may be further processed in the same way that events from an external event source are processed. 5.2. Event sources 5.2.1. Event sources A Knative event source can be any Kubernetes object that generates or imports cloud events, and relays those events to another endpoint, known as a sink . Sourcing events is critical to developing a distributed system that reacts to events. You can create and manage Knative event sources by using the Developer perspective in the OpenShift Container Platform web console, the Knative ( kn ) CLI, or by applying YAML files. Currently, OpenShift Serverless supports the following event source types: API server source Brings Kubernetes API server events into Knative. The API server source sends a new event each time a Kubernetes resource is created, updated or deleted. Ping source Produces events with a fixed payload on a specified cron schedule. Kafka event source Connects a Kafka cluster to a sink as an event source. You can also create a custom event source . 5.2.2. Event source in the Administrator perspective Sourcing events is critical to developing a distributed system that reacts to events. 5.2.2.1. Creating an event source by using the Administrator perspective A Knative event source can be any Kubernetes object that generates or imports cloud events, and relays those events to another endpoint, known as a sink . Prerequisites The OpenShift Serverless Operator and Knative Eventing are installed on your OpenShift Container Platform cluster. You have logged in to the web console and are in the Administrator perspective. You have cluster administrator permissions for OpenShift Container Platform. Procedure In the Administrator perspective of the OpenShift Container Platform web console, navigate to Serverless Eventing . In the Create list, select Event Source . You will be directed to the Event Sources page. Select the event source type that you want to create. 5.2.3. 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. 5.2.3.1. 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 . 5.2.3.2. 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 5.2.3.2.1. 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 . 5.2.3.3. 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 5.2.4. 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. 5.2.4.1. 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 . 5.2.4.2. 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> 5.2.4.2.1. 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 . 5.2.4.3. 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 5.2.5. 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. 5.2.5.1. 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. 5.2.5.2. 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! 5.2.5.2.1. 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 . 5.2.5.3. 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 5.2.5.4. Configuring SASL authentication for Kafka sources Simple Authentication and Security Layer (SASL) is used by Apache Kafka for authentication. If you use SASL authentication on your cluster, users must provide credentials to Knative for communicating with the Kafka cluster; otherwise events cannot be produced or consumed. Prerequisites You have cluster or dedicated administrator permissions on OpenShift Container Platform. The OpenShift Serverless Operator, Knative Eventing, and the KnativeKafka CR 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 a username and password for a Kafka cluster. You have chosen the SASL mechanism to use, for example, PLAIN , SCRAM-SHA-256 , or SCRAM-SHA-512 . If TLS is enabled, you also need the ca.crt certificate file for the Kafka cluster. You have installed the OpenShift ( oc ) CLI. Procedure Create the certificate files as secrets in your chosen namespace: USD oc create secret -n <namespace> generic <kafka_auth_secret> \ --from-file=ca.crt=caroot.pem \ --from-literal=password="SecretPassword" \ --from-literal=saslType="SCRAM-SHA-512" \ 1 --from-literal=user="my-sasl-user" 1 The SASL type can be PLAIN , SCRAM-SHA-256 , or SCRAM-SHA-512 . Create or modify your Kafka source so that it contains the following spec configuration: apiVersion: sources.knative.dev/v1beta1 kind: KafkaSource metadata: name: example-source spec: ... net: sasl: enable: true user: secretKeyRef: name: <kafka_auth_secret> key: user password: secretKeyRef: name: <kafka_auth_secret> key: password type: secretKeyRef: name: <kafka_auth_secret> key: saslType tls: enable: true caCert: 1 secretKeyRef: name: <kafka_auth_secret> key: ca.crt ... 1 The caCert spec is not required if you are using a public cloud Kafka service, such as Red Hat OpenShift Streams for Apache Kafka. 5.2.6. 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. 5.2.6.1. 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. Note The SinkBinding object currently does not support custom revision names for services. 5.2.6.1.1. 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/v1 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": "" } 5.2.6.1.2. 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/v1 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": "" } 5.2.6.1.2.1. 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 . 5.2.6.1.3. 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. 5.2.6.1.4. 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 5.2.6.1.4.1. 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 ... 5.2.6.1.4.2. 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" } } 5.2.6.1.4.3. 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 5.2.6.2. 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. 5.2.6.2.1. 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 ... 5.2.6.2.2. 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> 5.2.6.2.3. 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 . 5.2.6.2.4. 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" ... 5.2.6.2.4.1. 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" } } 5.2.7. Connecting 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 that events are sent to from that source. The sink can be any addressable or callable resource that can receive incoming events from other resources. 5.2.7.1. Connect an event source to a sink using the Developer perspective 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 Source and 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 the connected sink to see the sink details in the right panel. 5.3. Event sinks 5.3.1. 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. 5.3.1.1. 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 . 5.3.2. 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. 5.3.2.1. 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. By default, a Kafka sink uses the binary content mode, which is more efficient than the structured mode. 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. 5.3.2.2. Configuring security for Kafka sinks Transport Layer Security (TLS) is used by Apache Kafka clients and servers to encrypt traffic between Knative and Kafka, as well as for authentication. TLS is the only supported method of traffic encryption for Knative Kafka. Simple Authentication and Security Layer (SASL) is used by Apache Kafka for authentication. If you use SASL authentication on your cluster, users must provide credentials to Knative for communicating with the Kafka cluster; otherwise events cannot be produced or consumed. Prerequisites The OpenShift Serverless Operator, Knative Eventing, and the KnativeKafka custom resources (CRs) are installed on your OpenShift Container Platform cluster. Kafka sink is enabled in the KnativeKafka CR. 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 a Kafka cluster CA certificate stored as a .pem file. You have a Kafka cluster client certificate and a key stored as .pem files. You have installed the OpenShift ( oc ) CLI. You have chosen the SASL mechanism to use, for example, PLAIN , SCRAM-SHA-256 , or SCRAM-SHA-512 . Procedure Create the certificate files as a secret in the same namespace as your KafkaSink object: Important Certificates and keys must be in PEM format. For authentication using SASL without encryption: USD oc create secret -n <namespace> generic <secret_name> \ --from-literal=protocol=SASL_PLAINTEXT \ --from-literal=sasl.mechanism=<sasl_mechanism> \ --from-literal=user=<username> \ --from-literal=password=<password> For authentication using SASL and encryption using TLS: USD oc create secret -n <namespace> generic <secret_name> \ --from-literal=protocol=SASL_SSL \ --from-literal=sasl.mechanism=<sasl_mechanism> \ --from-file=ca.crt=<my_caroot.pem_file_path> \ 1 --from-literal=user=<username> \ --from-literal=password=<password> 1 The ca.crt can be omitted to use the system's root CA set if you are using a public cloud managed Kafka service, such as Red Hat OpenShift Streams for Apache Kafka. For authentication and encryption using TLS: USD oc create secret -n <namespace> generic <secret_name> \ --from-literal=protocol=SSL \ --from-file=ca.crt=<my_caroot.pem_file_path> \ 1 --from-file=user.crt=<my_cert.pem_file_path> \ --from-file=user.key=<my_key.pem_file_path> 1 The ca.crt can be omitted to use the system's root CA set if you are using a public cloud managed Kafka service, such as Red Hat OpenShift Streams for Apache Kafka. Create or modify a KafkaSink object and add a reference to your secret in the auth spec: apiVersion: eventing.knative.dev/v1alpha1 kind: KafkaSink metadata: name: <sink_name> namespace: <namespace> spec: ... auth: secret: ref: name: <secret_name> ... Apply the KafkaSink object: USD oc apply -f <filename> 5.4. Brokers 5.4.1. Brokers 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. 5.4.2. Broker types Cluster administrators can set the default broker implementation for a cluster. When you create a broker, the default broker implementation is used, unless you provide set configurations in the Broker object. 5.4.2.1. Default broker implementation for development purposes 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. The default broker is backed by the InMemoryChannel channel implementation by default. If you want to use Kafka to reduce network hops, use the Kafka broker implementation. Do not configure the channel-based broker to be backed by the KafkaChannel channel implementation. 5.4.2.2. Production-ready Kafka broker implementation 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. 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. 5.4.3. 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. 5.4.3.1. 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: 5.4.3.2. 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: 5.4.3.3. 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: 5.4.3.4. 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 5.4.3.5. Creating a broker by using the web console After Knative Eventing is installed on your cluster, you can create a broker by using the web console. Using the OpenShift Container Platform web console provides a streamlined and intuitive user interface to create a broker. 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 In the Developer perspective, navigate to +Add Broker . The Broker page is displayed. Optional. Update the Name of the broker. If you do not update the name, the generated broker is named default . Click Create . Verification You can verify that the broker was created by viewing broker components in the Topology page. In the Developer perspective, navigate to Topology . View the mt-broker-ingress , mt-broker-filter , and mt-broker-controller components. 5.4.3.6. Creating a broker by using the Administrator perspective 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. Prerequisites The OpenShift Serverless Operator and Knative Eventing are installed on your OpenShift Container Platform cluster. You have logged in to the web console and are in the Administrator perspective. You have cluster administrator permissions for OpenShift Container Platform. Procedure In the Administrator perspective of the OpenShift Container Platform web console, navigate to Serverless Eventing . In the Create list, select Broker . You will be directed to the Create Broker page. Optional: Modify the YAML configuration for the broker. Click Create . 5.4.3.7. 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 . 5.4.3.8. Additional resources Configuring the default broker class Triggers Event sources Event delivery 5.4.4. Configuring the default broker backing channel If you are using a channel-based broker, you can set the default backing channel type for the broker to either InMemoryChannel or KafkaChannel . Prerequisites You have administrator permissions on OpenShift Container Platform. You have installed the OpenShift Serverless Operator and Knative Eventing on your cluster. You have installed the OpenShift ( oc ) CLI. If you want to use Kafka channels as the default backing channel type, you must also install the KnativeKafka CR on your cluster. Procedure Modify the KnativeEventing custom resource (CR) to add configuration details for the config-br-default-channel config map: apiVersion: operator.knative.dev/v1beta1 kind: KnativeEventing metadata: name: knative-eventing namespace: knative-eventing spec: config: 1 config-br-default-channel: channel-template-spec: | apiVersion: messaging.knative.dev/v1beta1 kind: KafkaChannel 2 spec: numPartitions: 6 3 replicationFactor: 3 4 1 In spec.config , you can specify the config maps that you want to add modified configurations for. 2 The default backing channel type configuration. In this example, the default channel implementation for the cluster is KafkaChannel . 3 The number of partitions for the Kafka channel that backs the broker. 4 The replication factor for the Kafka channel that backs the broker. Apply the updated KnativeEventing CR: USD oc apply -f <filename> 5.4.5. Configuring the default broker class You can use the config-br-defaults config map to specify default broker class settings for Knative Eventing. You can specify the default broker class for the entire cluster or for one or more namespaces. Currently the MTChannelBasedBroker and Kafka broker types are supported. Prerequisites You have administrator permissions on OpenShift Container Platform. You have installed the OpenShift Serverless Operator and Knative Eventing on your cluster. If you want to use Kafka broker as the default broker implementation, you must also install the KnativeKafka CR on your cluster. Procedure Modify the KnativeEventing custom resource to add configuration details for the config-br-defaults config map: apiVersion: operator.knative.dev/v1beta1 kind: KnativeEventing metadata: name: knative-eventing namespace: knative-eventing spec: defaultBrokerClass: Kafka 1 config: 2 config-br-defaults: 3 default-br-config: | clusterDefault: 4 brokerClass: Kafka apiVersion: v1 kind: ConfigMap name: kafka-broker-config 5 namespace: knative-eventing 6 namespaceDefaults: 7 my-namespace: brokerClass: MTChannelBasedBroker apiVersion: v1 kind: ConfigMap name: config-br-default-channel 8 namespace: knative-eventing 9 ... 1 The default broker class for Knative Eventing. 2 In spec.config , you can specify the config maps that you want to add modified configurations for. 3 The config-br-defaults config map specifies the default settings for any broker that does not specify spec.config settings or a broker class. 4 The cluster-wide default broker class configuration. In this example, the default broker class implementation for the cluster is Kafka . 5 The kafka-broker-config config map specifies default settings for the Kafka broker. See "Configuring Kafka broker settings" in the "Additional resources" section. 6 The namespace where the kafka-broker-config config map exists. 7 The namespace-scoped default broker class configuration. In this example, the default broker class implementation for the my-namespace namespace is MTChannelBasedBroker . You can specify default broker class implementations for multiple namespaces. 8 The config-br-default-channel config map specifies the default backing channel for the broker. See "Configuring the default broker backing channel" in the "Additional resources" section. 9 The namespace where the config-br-default-channel config map exists. Important Configuring a namespace-specific default overrides any cluster-wide settings. 5.4.6. Kafka broker 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. 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. 5.4.6.1. 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. 5.4.6.1.1. 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> 5.4.6.1.2. 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> 5.4.6.1.3. Knative Broker implementation for Apache Kafka with isolated data plane Important The Knative Broker implementation for Apache Kafka with isolated data plane 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 Technology Preview Features Support Scope . The Knative Broker implementation for Apache Kafka has 2 planes: Control plane Consists of controllers that talk to the Kubernetes API, watch for custom objects, and manage the data plane. Data plane The collection of components that listen for incoming events, talk to Apache Kafka, and send events to the event sinks. The Knative Broker implementation for Apache Kafka data plane is where events flow. The implementation consists of kafka-broker-receiver and kafka-broker-dispatcher deployments. When you configure a Broker class of Kafka , the Knative Broker implementation for Apache Kafka uses a shared data plane. This means that the kafka-broker-receiver and kafka-broker-dispatcher deployments in the knative-eventing namespace are used for all Apache Kafka Brokers in the cluster. However, when you configure a Broker class of KafkaNamespaced , the Apache Kafka broker controller creates a new data plane for each namespace where a broker exists. This data plane is used by all KafkaNamespaced brokers in that namespace. This provides isolation between the data planes, so that the kafka-broker-receiver and kafka-broker-dispatcher deployments in the user namespace are only used for the broker in that namespace. Important As a consequence of having separate data planes, this security feature creates more deployments and uses more resources. Unless you have such isolation requirements, use a regular Broker with a class of Kafka . 5.4.6.1.4. Creating a Knative broker for Apache Kafka that uses an isolated data plane Important The Knative Broker implementation for Apache Kafka with isolated data plane 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 Technology Preview Features Support Scope . To create a KafkaNamespaced broker, you must set the eventing.knative.dev/broker.class annotation to KafkaNamespaced . Prerequisites The OpenShift Serverless Operator, Knative Eventing, and the KnativeKafka custom resource are installed on your OpenShift Container Platform cluster. You have access to an Apache 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 an Apache Kafka-based broker by using a YAML file: apiVersion: eventing.knative.dev/v1 kind: Broker metadata: annotations: eventing.knative.dev/broker.class: KafkaNamespaced 1 name: default namespace: my-namespace 2 spec: config: apiVersion: v1 kind: ConfigMap name: my-config 3 ... 1 To use the Apache Kafka broker with isolated data planes, the broker class value must be KafkaNamespaced . 2 3 The referenced ConfigMap object my-config must be in the same namespace as the Broker object, in this case my-namespace . Apply the Apache Kafka-based broker YAML file: USD oc apply -f <filename> Important The ConfigMap object in spec.config must be in the same namespace as the Broker object: apiVersion: v1 kind: ConfigMap metadata: name: my-config namespace: my-namespace data: ... After the creation of the first Broker object with the KafkaNamespaced class, the kafka-broker-receiver and kafka-broker-dispatcher deployments are created in the namespace. Subsequently, all brokers with the KafkaNamespaced class in the same namespace will use the same data plane. If no brokers with the KafkaNamespaced class exist in the namespace, the data plane in the namespace is deleted. 5.4.6.2. Configuring Kafka broker settings You can configure the replication factor, bootstrap servers, and the number of topic partitions for a Kafka broker, by creating a config map and referencing this config map in the Kafka Broker object. Prerequisites You have cluster or dedicated administrator permissions on OpenShift Container Platform. The OpenShift Serverless Operator, Knative Eventing, and the KnativeKafka custom resource (CR) are installed on your OpenShift Container Platform cluster. You have created a project or have access to a project that has the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. You have installed the OpenShift CLI ( oc ). Procedure Modify the kafka-broker-config config map, or create your own config map that contains the following configuration: apiVersion: v1 kind: ConfigMap metadata: name: <config_map_name> 1 namespace: <namespace> 2 data: default.topic.partitions: <integer> 3 default.topic.replication.factor: <integer> 4 bootstrap.servers: <list_of_servers> 5 1 The config map name. 2 The namespace where the config map exists. 3 The number of topic partitions for the Kafka broker. This controls how quickly events can be sent to the broker. A higher number of partitions requires greater compute resources. 4 The replication factor of topic messages. This prevents against data loss. A higher replication factor requires greater compute resources and more storage. 5 A comma separated list of bootstrap servers. This can be inside or outside of the OpenShift Container Platform cluster, and is a list of Kafka clusters that the broker receives events from and sends events to. Important The default.topic.replication.factor value must be less than or equal to the number of Kafka broker instances in your cluster. For example, if you only have one Kafka broker, the default.topic.replication.factor value should not be more than "1" . Example Kafka broker config map apiVersion: v1 kind: ConfigMap metadata: name: kafka-broker-config namespace: knative-eventing data: default.topic.partitions: "10" default.topic.replication.factor: "3" bootstrap.servers: "my-cluster-kafka-bootstrap.kafka:9092" Apply the config map: USD oc apply -f <config_map_filename> Specify the config map for the Kafka Broker object: Example Broker object apiVersion: eventing.knative.dev/v1 kind: Broker metadata: name: <broker_name> 1 namespace: <namespace> 2 annotations: eventing.knative.dev/broker.class: Kafka 3 spec: config: apiVersion: v1 kind: ConfigMap name: <config_map_name> 4 namespace: <namespace> 5 ... 1 The broker name. 2 The namespace where the broker exists. 3 The broker class annotation. In this example, the broker is a Kafka broker that uses the class value Kafka . 4 The config map name. 5 The namespace where the config map exists. Apply the broker: USD oc apply -f <broker_filename> 5.4.6.3. Security configuration for Knative Kafka brokers Kafka clusters are generally secured by using the TLS or SASL authentication methods. You can configure a Kafka broker or channel to work against a protected Red Hat AMQ Streams cluster by using TLS or SASL. Note Red Hat recommends that you enable both SASL and TLS together. 5.4.6.3.1. Configuring TLS authentication for Kafka brokers Transport Layer Security (TLS) is used by Apache Kafka clients and servers to encrypt traffic between Knative and Kafka, as well as for authentication. TLS is the only supported method of traffic encryption for Knative Kafka. Prerequisites You have cluster or dedicated administrator permissions on OpenShift Container Platform. The OpenShift Serverless Operator, Knative Eventing, and the KnativeKafka CR 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 a Kafka cluster CA certificate stored as a .pem file. You have a Kafka cluster client certificate and a key stored as .pem files. Install the OpenShift CLI ( oc ). Procedure Create the certificate files as a secret in the knative-eventing namespace: USD oc create secret -n knative-eventing generic <secret_name> \ --from-literal=protocol=SSL \ --from-file=ca.crt=caroot.pem \ --from-file=user.crt=certificate.pem \ --from-file=user.key=key.pem Important Use the key names ca.crt , user.crt , and user.key . Do not change them. Edit the KnativeKafka CR and add a reference to your secret in the broker spec: apiVersion: operator.serverless.openshift.io/v1alpha1 kind: KnativeKafka metadata: namespace: knative-eventing name: knative-kafka spec: broker: enabled: true defaultConfig: authSecretName: <secret_name> ... 5.4.6.3.2. Configuring SASL authentication for Kafka brokers Simple Authentication and Security Layer (SASL) is used by Apache Kafka for authentication. If you use SASL authentication on your cluster, users must provide credentials to Knative for communicating with the Kafka cluster; otherwise events cannot be produced or consumed. Prerequisites You have cluster or dedicated administrator permissions on OpenShift Container Platform. The OpenShift Serverless Operator, Knative Eventing, and the KnativeKafka CR 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 a username and password for a Kafka cluster. You have chosen the SASL mechanism to use, for example, PLAIN , SCRAM-SHA-256 , or SCRAM-SHA-512 . If TLS is enabled, you also need the ca.crt certificate file for the Kafka cluster. Install the OpenShift CLI ( oc ). Procedure Create the certificate files as a secret in the knative-eventing namespace: USD oc create secret -n knative-eventing generic <secret_name> \ --from-literal=protocol=SASL_SSL \ --from-literal=sasl.mechanism=<sasl_mechanism> \ --from-file=ca.crt=caroot.pem \ --from-literal=password="SecretPassword" \ --from-literal=user="my-sasl-user" Use the key names ca.crt , password , and sasl.mechanism . Do not change them. If you want to use SASL with public CA certificates, you must use the tls.enabled=true flag, rather than the ca.crt argument, when creating the secret. For example: USD oc create secret -n <namespace> generic <kafka_auth_secret> \ --from-literal=tls.enabled=true \ --from-literal=password="SecretPassword" \ --from-literal=saslType="SCRAM-SHA-512" \ --from-literal=user="my-sasl-user" Edit the KnativeKafka CR and add a reference to your secret in the broker spec: apiVersion: operator.serverless.openshift.io/v1alpha1 kind: KnativeKafka metadata: namespace: knative-eventing name: knative-kafka spec: broker: enabled: true defaultConfig: authSecretName: <secret_name> ... 5.4.6.4. Additional resources Red Hat AMQ Streams documentation TLS and SASL on Kafka 5.4.7. Managing brokers The Knative ( kn ) CLI provides commands that can be used to describe and list existing brokers. 5.4.7.1. 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 5.4.7.2. 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 5.4.8. 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. 5.4.8.1. Event delivery behavior patterns for channels and brokers Different channel and broker types have their own behavior patterns that are followed for event delivery. 5.4.8.1.1. 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. 5.4.8.2. 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> . 5.4.8.3. 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> ... 5.4.8.4. 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> 5.5. Triggers 5.5.1. Triggers overview 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 . 5.5.1.1. 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> 5.5.1.2. 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 . 5.5.2. Creating 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. 5.5.2.1. Creating a trigger by using the Administrator perspective 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 and Knative Eventing are installed on your OpenShift Container Platform cluster. You have logged in to the web console and are in the Administrator perspective. You have cluster administrator permissions for OpenShift Container Platform. You have created a Knative broker. You have created a Knative service to use as a subscriber. Procedure In the Administrator perspective of the OpenShift Container Platform web console, navigate to Serverless Eventing . In the Broker tab, select the Options menu for the broker that you want to add a trigger to. Click Add Trigger in the list. In the Add Trigger dialogue box, select a Subscriber for the trigger. The subscriber is the Knative service that will receive events from the broker. Click Add . 5.5.2.2. Creating a trigger by using the Developer perspective 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 . 5.5.2.3. Creating a trigger by using the Knative CLI 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. 5.5.3. List triggers from the command line Using the Knative ( kn ) CLI to list triggers provides a streamlined and intuitive user interface. 5.5.3.1. Listing triggers by using the Knative CLI 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 5.5.4. Describe triggers from the command line Using the Knative ( kn ) CLI to describe triggers provides a streamlined and intuitive user interface. 5.5.4.1. Describing a trigger by using the Knative CLI 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 5.5.5. 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. 5.5.6. Filtering triggers from the command line 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. 5.5.6.1. Filtering events with triggers by using the Knative CLI 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 5.5.7. Updating triggers from the command line Using the Knative ( kn ) CLI to update triggers provides a streamlined and intuitive user interface. 5.5.7.1. Updating a trigger by using the Knative CLI 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 5.5.8. Deleting triggers from the command line Using the Knative ( kn ) CLI to delete a trigger provides a streamlined and intuitive user interface. 5.5.8.1. Deleting a trigger by using the Knative CLI 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. 5.6. Channels 5.6.1. Channels and subscriptions 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. After you create a Channel object, a mutating admission webhook adds a set of spec.channelTemplate properties for the Channel object based on the default channel implementation. For example, for an InMemoryChannel default implementation, the Channel object looks as follows: apiVersion: messaging.knative.dev/v1 kind: Channel metadata: name: example-channel namespace: default spec: channelTemplate: apiVersion: messaging.knative.dev/v1 kind: InMemoryChannel The channel controller then creates the backing channel instance based on the spec.channelTemplate configuration. Note The spec.channelTemplate properties cannot be changed after creation, because they are set by the default channel mechanism rather than by the user. When this mechanism is used with the preceding example, two objects are created: a generic backing channel and an InMemoryChannel channel. If you are using a different default channel implementation, the InMemoryChannel is replaced with one that is specific to your implementation. For example, with Knative Kafka, the KafkaChannel channel is created. The backing channel acts as a proxy that copies its subscriptions to the user-created channel object, and sets the user-created channel object status to reflect the status of the backing channel. 5.6.1.1. Channel implementation types InMemoryChannel and KafkaChannel channel implementations can be used with OpenShift Serverless for development use. The following are limitations of InMemoryChannel type channels: No event persistence is available. If a pod goes down, events on that pod are lost. InMemoryChannel channels do not implement event ordering, so two events that are received in the channel at the same time can be delivered to a subscriber in any order. If a subscriber rejects an event, there are no re-delivery attempts by default. You can configure re-delivery attempts by modifying the delivery spec in the Subscription object. 5.6.2. 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. 5.6.2.1. Creating a channel by using the Administrator perspective After Knative Eventing is installed on your cluster, you can create a channel by using the Administrator perspective. Prerequisites The OpenShift Serverless Operator and Knative Eventing are installed on your OpenShift Container Platform cluster. You have logged in to the web console and are in the Administrator perspective. You have cluster administrator permissions for OpenShift Container Platform. Procedure In the Administrator perspective of the OpenShift Container Platform web console, navigate to Serverless Eventing . In the Create list, select Channel . You will be directed to the Channel page. Select the type of Channel object that you want to create in the Type list. Note Currently only InMemoryChannel channel objects are supported by default. Kafka channels are available if you have installed Knative Kafka on OpenShift Serverless. Click Create . 5.6.2.2. Creating a channel by using the Developer perspective 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. 5.6.2.3. 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> 5.6.2.4. 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> 5.6.2.5. 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> 5.6.2.6. 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 . 5.6.3. Default channel implementation You can use the default-ch-webhook config map to specify the default channel implementation of Knative Eventing. You can specify the default channel implementation for the entire cluster or for one or more namespaces. Currently the InMemoryChannel and KafkaChannel channel types are supported. 5.6.3.1. Configuring the default channel implementation Prerequisites You have administrator permissions on OpenShift Container Platform. You have installed the OpenShift Serverless Operator and Knative Eventing on your cluster. If you want to use Kafka channels as the default channel implementation, you must also install the KnativeKafka CR on your cluster. Procedure Modify the KnativeEventing custom resource to add configuration details for the default-ch-webhook config map: apiVersion: operator.knative.dev/v1beta1 kind: KnativeEventing metadata: name: knative-eventing namespace: knative-eventing spec: config: 1 default-ch-webhook: 2 default-ch-config: | clusterDefault: 3 apiVersion: messaging.knative.dev/v1 kind: InMemoryChannel spec: delivery: backoffDelay: PT0.5S backoffPolicy: exponential retry: 5 namespaceDefaults: 4 my-namespace: apiVersion: messaging.knative.dev/v1beta1 kind: KafkaChannel spec: numPartitions: 1 replicationFactor: 1 1 In spec.config , you can specify the config maps that you want to add modified configurations for. 2 The default-ch-webhook config map can be used to specify the default channel implementation for the cluster or for one or more namespaces. 3 The cluster-wide default channel type configuration. In this example, the default channel implementation for the cluster is InMemoryChannel . 4 The namespace-scoped default channel type configuration. In this example, the default channel implementation for the my-namespace namespace is KafkaChannel . Important Configuring a namespace-specific default overrides any cluster-wide settings. 5.6.4. Security configuration for Knative Kafka channels 5.6.4.1. Configuring TLS authentication for Kafka channels Transport Layer Security (TLS) is used by Apache Kafka clients and servers to encrypt traffic between Knative and Kafka, as well as for authentication. TLS is the only supported method of traffic encryption for Knative Kafka. Prerequisites You have cluster or dedicated administrator permissions on OpenShift Container Platform. The OpenShift Serverless Operator, Knative Eventing, and the KnativeKafka CR 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 a Kafka cluster CA certificate stored as a .pem file. You have a Kafka cluster client certificate and a key stored as .pem files. Install the OpenShift CLI ( oc ). Procedure Create the certificate files as secrets in your chosen namespace: USD oc create secret -n <namespace> generic <kafka_auth_secret> \ --from-file=ca.crt=caroot.pem \ --from-file=user.crt=certificate.pem \ --from-file=user.key=key.pem Important Use the key names ca.crt , user.crt , and user.key . Do not change them. Start editing the KnativeKafka custom resource: USD oc edit knativekafka Reference your secret and the namespace of the secret: apiVersion: operator.serverless.openshift.io/v1alpha1 kind: KnativeKafka metadata: namespace: knative-eventing name: knative-kafka spec: channel: authSecretName: <kafka_auth_secret> authSecretNamespace: <kafka_auth_secret_namespace> bootstrapServers: <bootstrap_servers> enabled: true source: enabled: true Note Make sure to specify the matching port in the bootstrap server. For example: apiVersion: operator.serverless.openshift.io/v1alpha1 kind: KnativeKafka metadata: namespace: knative-eventing name: knative-kafka spec: channel: authSecretName: tls-user authSecretNamespace: kafka bootstrapServers: eventing-kafka-bootstrap.kafka.svc:9094 enabled: true source: enabled: true 5.6.4.2. Configuring SASL authentication for Kafka channels Simple Authentication and Security Layer (SASL) is used by Apache Kafka for authentication. If you use SASL authentication on your cluster, users must provide credentials to Knative for communicating with the Kafka cluster; otherwise events cannot be produced or consumed. Prerequisites You have cluster or dedicated administrator permissions on OpenShift Container Platform. The OpenShift Serverless Operator, Knative Eventing, and the KnativeKafka CR 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 a username and password for a Kafka cluster. You have chosen the SASL mechanism to use, for example, PLAIN , SCRAM-SHA-256 , or SCRAM-SHA-512 . If TLS is enabled, you also need the ca.crt certificate file for the Kafka cluster. Install the OpenShift CLI ( oc ). Procedure Create the certificate files as secrets in your chosen namespace: USD oc create secret -n <namespace> generic <kafka_auth_secret> \ --from-file=ca.crt=caroot.pem \ --from-literal=password="SecretPassword" \ --from-literal=saslType="SCRAM-SHA-512" \ --from-literal=user="my-sasl-user" Use the key names ca.crt , password , and sasl.mechanism . Do not change them. If you want to use SASL with public CA certificates, you must use the tls.enabled=true flag, rather than the ca.crt argument, when creating the secret. For example: USD oc create secret -n <namespace> generic <kafka_auth_secret> \ --from-literal=tls.enabled=true \ --from-literal=password="SecretPassword" \ --from-literal=saslType="SCRAM-SHA-512" \ --from-literal=user="my-sasl-user" Start editing the KnativeKafka custom resource: USD oc edit knativekafka Reference your secret and the namespace of the secret: apiVersion: operator.serverless.openshift.io/v1alpha1 kind: KnativeKafka metadata: namespace: knative-eventing name: knative-kafka spec: channel: authSecretName: <kafka_auth_secret> authSecretNamespace: <kafka_auth_secret_namespace> bootstrapServers: <bootstrap_servers> enabled: true source: enabled: true Note Make sure to specify the matching port in the bootstrap server. For example: apiVersion: operator.serverless.openshift.io/v1alpha1 kind: KnativeKafka metadata: namespace: knative-eventing name: knative-kafka spec: channel: authSecretName: scram-user authSecretNamespace: kafka bootstrapServers: eventing-kafka-bootstrap.kafka.svc:9093 enabled: true source: enabled: true 5.7. Subscriptions 5.7.1. Creating 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. 5.7.1.1. Creating a subscription by using the Administrator perspective After you have created a channel and an event sink, also known as a subscriber , you can create a subscription to enable event delivery. Subscriptions are created by configuring a Subscription object, which specifies the channel and the subscriber to deliver events to. You can also specify some subscriber-specific options, such as how to handle failures. Prerequisites The OpenShift Serverless Operator and Knative Eventing are installed on your OpenShift Container Platform cluster. You have logged in to the web console and are in the Administrator perspective. You have cluster administrator permissions for OpenShift Container Platform. You have created a Knative channel. You have created a Knative service to use as a subscriber. Procedure In the Administrator perspective of the OpenShift Container Platform web console, navigate to Serverless Eventing . In the Channel tab, select the Options menu for the channel that you want to add a subscription to. Click Add Subscription in the list. In the Add Subscription dialogue box, select a Subscriber for the subscription. The subscriber is the Knative service that receives events from the channel. Click Add . 5.7.1.2. Creating a subscription by using the Developer perspective 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: 5.7.1.3. 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> 5.7.1.4. 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> 5.7.1.5. 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 . 5.7.2. Managing subscriptions 5.7.2.1. 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 5.7.2.2. 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 5.7.2.3. 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 5.8. Event discovery 5.8.1. 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. 5.8.2. Listing event source types from the command line Using the Knative ( kn ) CLI provides a streamlined and intuitive user interface to view available event source types on your cluster. 5.8.2.1. Listing available event source types by using the Knative CLI 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 5.8.3. Listing event source types from 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. 5.8.3.1. Viewing available event source types within the Developer perspective 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. 5.8.4. Listing event sources from the command line Using the Knative ( kn ) CLI provides a streamlined and intuitive user interface to view existing event sources on your cluster. 5.8.4.1. Listing available event sources by using the Knative CLI 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 5.9. Tuning eventing configuration 5.9.1. Overriding Knative Eventing system deployment configurations You can override the default configurations for some specific deployments by modifying the deployments spec in the KnativeEventing custom resource (CR). Currently, overriding default configuration settings is supported for the eventing-controller , eventing-webhook , and imc-controller fields, as well as for the readiness and liveness fields for probes. Important The replicas spec cannot override the number of replicas for deployments that use the Horizontal Pod Autoscaler (HPA), and does not work for the eventing-webhook deployment. Note You can only override probes that are defined in the deployment by default. All Knative Serving deployments define a readiness and a liveness probe by default, with these exceptions: net-kourier-controller and 3scale-kourier-gateway only define a readiness probe. net-istio-controller and net-istio-webhook define no probes. 5.9.1.1. Overriding deployment configurations Currently, overriding default configuration settings is supported for the eventing-controller , eventing-webhook , and imc-controller fields, as well as for the readiness and liveness fields for probes. Important The replicas spec cannot override the number of replicas for deployments that use the Horizontal Pod Autoscaler (HPA), and does not work for the eventing-webhook deployment. In the following example, a KnativeEventing CR overrides the eventing-controller deployment so that: The readiness probe timeout eventing-controller is set to be 10 seconds. The deployment has specified CPU and memory resource limits. The deployment has 3 replicas. The example-label: label label is added. The example-annotation: annotation annotation is added. The nodeSelector field is set to select nodes with the disktype: hdd label. KnativeEventing CR example apiVersion: operator.knative.dev/v1beta1 kind: KnativeEventing metadata: name: knative-eventing namespace: knative-eventing spec: deployments: - name: eventing-controller readinessProbes: 1 - container: controller timeoutSeconds: 10 resources: - container: eventing-controller requests: cpu: 300m memory: 100Mi limits: cpu: 1000m memory: 250Mi replicas: 3 labels: example-label: label annotations: example-annotation: annotation nodeSelector: disktype: hdd 1 You can use the readiness and liveness probe overrides to override all fields of a probe in a container of a deployment as specified in the Kubernetes API except for the fields related to the probe handler: exec , grpc , httpGet , and tcpSocket . Note The KnativeEventing CR label and annotation settings override the deployment's labels and annotations for both the deployment itself and the resulting pods. Additional resources Probe configuration section of the Kubernetes API documentation 5.9.2. High availability High availability (HA) is a standard feature of Kubernetes APIs that helps to ensure that APIs stay operational if a disruption occurs. In an HA deployment, if an active controller crashes or is deleted, another controller is readily available. This controller takes over processing of the APIs that were being serviced by the controller that is now unavailable. HA in OpenShift Serverless is available through leader election, which is enabled by default after the Knative Serving or Eventing control plane is installed. When using a leader election HA pattern, instances of controllers are already scheduled and running inside the cluster before they are required. These controller instances compete to use a shared resource, known as the leader election lock. The instance of the controller that has access to the leader election lock resource at any given time is called the leader. HA in OpenShift Serverless is available through leader election, which is enabled by default after the Knative Serving or Eventing control plane is installed. When using a leader election HA pattern, instances of controllers are already scheduled and running inside the cluster before they are required. These controller instances compete to use a shared resource, known as the leader election lock. The instance of the controller that has access to the leader election lock resource at any given time is called the leader. 5.9.2.1. Configuring high availability replicas for Knative Eventing High availability (HA) is available by default for the Knative Eventing eventing-controller , eventing-webhook , imc-controller , imc-dispatcher , and mt-broker-controller components, which are configured to have two replicas each by default. You can change the number of replicas for these components by modifying the spec.high-availability.replicas value in the KnativeEventing custom resource (CR). Note For Knative Eventing, the mt-broker-filter and mt-broker-ingress deployments are not scaled by HA. If multiple deployments are needed, scale these components manually. Prerequisites You have access to an OpenShift Container Platform account with cluster administrator access. The OpenShift Serverless Operator and Knative Eventing are installed on your cluster. Procedure In the OpenShift Container Platform web console Administrator perspective, navigate to OperatorHub Installed Operators . Select the knative-eventing namespace. Click Knative Eventing in the list of Provided APIs for the OpenShift Serverless Operator to go to the Knative Eventing tab. Click knative-eventing , then go to the YAML tab in the knative-eventing page. Modify the number of replicas in the KnativeEventing CR: Example YAML apiVersion: operator.knative.dev/v1beta1 kind: KnativeEventing metadata: name: knative-eventing namespace: knative-eventing spec: high-availability: replicas: 3 5.9.2.2. Configuring high availability replicas for Knative Kafka High availability (HA) is available by default for the Knative Kafka kafka-controller and kafka-webhook-eventing components, which are configured to have two each replicas by default. You can change the number of replicas for these components by modifying the spec.high-availability.replicas value in the KnativeKafka custom resource (CR). Prerequisites You have access to an OpenShift Container Platform account with cluster administrator access. The OpenShift Serverless Operator and Knative Kafka are installed on your cluster. Procedure In the OpenShift Container Platform web console Administrator perspective, navigate to OperatorHub Installed Operators . Select the knative-eventing namespace. Click Knative Kafka in the list of Provided APIs for the OpenShift Serverless Operator to go to the Knative Kafka tab. Click knative-kafka , then go to the YAML tab in the knative-kafka page. Modify the number of replicas in the KnativeKafka CR: Example YAML apiVersion: operator.serverless.openshift.io/v1alpha1 kind: KnativeKafka metadata: name: knative-kafka namespace: knative-eventing spec: high-availability: replicas: 3

Commands:
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
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
oc create secret -n <namespace> generic <kafka_auth_secret> --from-file=ca.crt=caroot.pem --from-literal=password="SecretPassword" --from-literal=saslType="SCRAM-SHA-512" \ 1 --from-literal=user="my-sasl-user"
apiVersion: sources.knative.dev/v1beta1 kind: KafkaSource metadata: name: example-source spec: net: sasl: enable: true user: secretKeyRef: name: <kafka_auth_secret> key: user password: secretKeyRef: name: <kafka_auth_secret> key: password type: secretKeyRef: name: <kafka_auth_secret> key: saslType tls: enable: true caCert: 1 secretKeyRef: name: <kafka_auth_secret> key: ca.crt
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/v1 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/v1 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 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/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
oc create secret -n <namespace> generic <secret_name> --from-literal=protocol=SASL_PLAINTEXT --from-literal=sasl.mechanism=<sasl_mechanism> --from-literal=user=<username> --from-literal=password=<password>
oc create secret -n <namespace> generic <secret_name> --from-literal=protocol=SASL_SSL --from-literal=sasl.mechanism=<sasl_mechanism> --from-file=ca.crt=<my_caroot.pem_file_path> \ 1 --from-literal=user=<username> --from-literal=password=<password>
oc create secret -n <namespace> generic <secret_name> --from-literal=protocol=SSL --from-file=ca.crt=<my_caroot.pem_file_path> \ 1 --from-file=user.crt=<my_cert.pem_file_path> --from-file=user.key=<my_key.pem_file_path>
apiVersion: eventing.knative.dev/v1alpha1 kind: KafkaSink metadata: name: <sink_name> namespace: <namespace> spec: auth: secret: ref: name: <secret_name>
oc apply -f <filename>
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: operator.knative.dev/v1beta1 kind: KnativeEventing metadata: name: knative-eventing namespace: knative-eventing spec: config: 1 config-br-default-channel: channel-template-spec: | apiVersion: messaging.knative.dev/v1beta1 kind: KafkaChannel 2 spec: numPartitions: 6 3 replicationFactor: 3 4
oc apply -f <filename>
apiVersion: operator.knative.dev/v1beta1 kind: KnativeEventing metadata: name: knative-eventing namespace: knative-eventing spec: defaultBrokerClass: Kafka 1 config: 2 config-br-defaults: 3 default-br-config: | clusterDefault: 4 brokerClass: Kafka apiVersion: v1 kind: ConfigMap name: kafka-broker-config 5 namespace: knative-eventing 6 namespaceDefaults: 7 my-namespace: brokerClass: MTChannelBasedBroker apiVersion: v1 kind: ConfigMap name: config-br-default-channel 8 namespace: knative-eventing 9
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>
apiVersion: eventing.knative.dev/v1 kind: Broker metadata: annotations: eventing.knative.dev/broker.class: KafkaNamespaced 1 name: default namespace: my-namespace 2 spec: config: apiVersion: v1 kind: ConfigMap name: my-config 3
oc apply -f <filename>
apiVersion: v1 kind: ConfigMap metadata: name: my-config namespace: my-namespace data:
apiVersion: v1 kind: ConfigMap metadata: name: <config_map_name> 1 namespace: <namespace> 2 data: default.topic.partitions: <integer> 3 default.topic.replication.factor: <integer> 4 bootstrap.servers: <list_of_servers> 5
apiVersion: v1 kind: ConfigMap metadata: name: kafka-broker-config namespace: knative-eventing data: default.topic.partitions: "10" default.topic.replication.factor: "3" bootstrap.servers: "my-cluster-kafka-bootstrap.kafka:9092"
oc apply -f <config_map_filename>
apiVersion: eventing.knative.dev/v1 kind: Broker metadata: name: <broker_name> 1 namespace: <namespace> 2 annotations: eventing.knative.dev/broker.class: Kafka 3 spec: config: apiVersion: v1 kind: ConfigMap name: <config_map_name> 4 namespace: <namespace> 5
oc apply -f <broker_filename>
oc create secret -n knative-eventing generic <secret_name> --from-literal=protocol=SSL --from-file=ca.crt=caroot.pem --from-file=user.crt=certificate.pem --from-file=user.key=key.pem
apiVersion: operator.serverless.openshift.io/v1alpha1 kind: KnativeKafka metadata: namespace: knative-eventing name: knative-kafka spec: broker: enabled: true defaultConfig: authSecretName: <secret_name>
oc create secret -n knative-eventing generic <secret_name> --from-literal=protocol=SASL_SSL --from-literal=sasl.mechanism=<sasl_mechanism> --from-file=ca.crt=caroot.pem --from-literal=password="SecretPassword" --from-literal=user="my-sasl-user"
oc create secret -n <namespace> generic <kafka_auth_secret> --from-literal=tls.enabled=true --from-literal=password="SecretPassword" --from-literal=saslType="SCRAM-SHA-512" --from-literal=user="my-sasl-user"
apiVersion: operator.serverless.openshift.io/v1alpha1 kind: KnativeKafka metadata: namespace: knative-eventing name: knative-kafka spec: broker: enabled: true defaultConfig: authSecretName: <secret_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
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
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>
apiVersion: eventing.knative.dev/v1 kind: Trigger metadata: name: <trigger_name> annotations: kafka.eventing.knative.dev/delivery.order: ordered
oc apply -f <filename>
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
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
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: messaging.knative.dev/v1 kind: Channel metadata: name: example-channel namespace: default spec: channelTemplate: apiVersion: messaging.knative.dev/v1 kind: InMemoryChannel
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: operator.knative.dev/v1beta1 kind: KnativeEventing metadata: name: knative-eventing namespace: knative-eventing spec: config: 1 default-ch-webhook: 2 default-ch-config: | clusterDefault: 3 apiVersion: messaging.knative.dev/v1 kind: InMemoryChannel spec: delivery: backoffDelay: PT0.5S backoffPolicy: exponential retry: 5 namespaceDefaults: 4 my-namespace: apiVersion: messaging.knative.dev/v1beta1 kind: KafkaChannel spec: numPartitions: 1 replicationFactor: 1
oc create secret -n <namespace> generic <kafka_auth_secret> --from-file=ca.crt=caroot.pem --from-file=user.crt=certificate.pem --from-file=user.key=key.pem
oc edit knativekafka
apiVersion: operator.serverless.openshift.io/v1alpha1 kind: KnativeKafka metadata: namespace: knative-eventing name: knative-kafka spec: channel: authSecretName: <kafka_auth_secret> authSecretNamespace: <kafka_auth_secret_namespace> bootstrapServers: <bootstrap_servers> enabled: true source: enabled: true
apiVersion: operator.serverless.openshift.io/v1alpha1 kind: KnativeKafka metadata: namespace: knative-eventing name: knative-kafka spec: channel: authSecretName: tls-user authSecretNamespace: kafka bootstrapServers: eventing-kafka-bootstrap.kafka.svc:9094 enabled: true source: enabled: true
oc create secret -n <namespace> generic <kafka_auth_secret> --from-file=ca.crt=caroot.pem --from-literal=password="SecretPassword" --from-literal=saslType="SCRAM-SHA-512" --from-literal=user="my-sasl-user"
oc create secret -n <namespace> generic <kafka_auth_secret> --from-literal=tls.enabled=true --from-literal=password="SecretPassword" --from-literal=saslType="SCRAM-SHA-512" --from-literal=user="my-sasl-user"
oc edit knativekafka
apiVersion: operator.serverless.openshift.io/v1alpha1 kind: KnativeKafka metadata: namespace: knative-eventing name: knative-kafka spec: channel: authSecretName: <kafka_auth_secret> authSecretNamespace: <kafka_auth_secret_namespace> bootstrapServers: <bootstrap_servers> enabled: true source: enabled: true
apiVersion: operator.serverless.openshift.io/v1alpha1 kind: KnativeKafka metadata: namespace: knative-eventing name: knative-kafka spec: channel: authSecretName: scram-user authSecretNamespace: kafka bootstrapServers: eventing-kafka-bootstrap.kafka.svc:9093 enabled: true source: enabled: true
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 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: operator.knative.dev/v1beta1 kind: KnativeEventing metadata: name: knative-eventing namespace: knative-eventing spec: deployments: - name: eventing-controller readinessProbes: 1 - container: controller timeoutSeconds: 10 resources: - container: eventing-controller requests: cpu: 300m memory: 100Mi limits: cpu: 1000m memory: 250Mi replicas: 3 labels: example-label: label annotations: example-annotation: annotation nodeSelector: disktype: hdd
apiVersion: operator.knative.dev/v1beta1 kind: KnativeEventing metadata: name: knative-eventing namespace: knative-eventing spec: high-availability: replicas: 3
apiVersion: operator.serverless.openshift.io/v1alpha1 kind: KnativeKafka metadata: name: knative-kafka namespace: knative-eventing spec: high-availability: replicas: 3