Chapter 2. Using Service Mesh to isolate network traffic with OpenShift Serverless Important Using Service Mesh to isolate network traffic with OpenShift Serverless 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 . Service Mesh can be used to isolate network traffic between tenants on a shared Red Hat OpenShift Serverless cluster using Service Mesh AuthorizationPolicy resources. Serverless can also leverage this, using several Service Mesh resources. A tenant is a group of one or multiple projects that can access each other over the network on a shared cluster. 2.1. Prerequisites You have access to an Red Hat OpenShift Serverless account with cluster administrator access. You have set up the Service Mesh and Serverless integration. You have created one or more OpenShift projects for each tenant. 2.2. High-level architecture The high-level architecture of Serverless traffic isolation provided by Service Mesh consists of AuthorizationPolicy objects in the knative-serving , knative-eventing , and the tenants' namespaces, with all the components being part of the Service Mesh. The injected Service Mesh sidecars enforce those rules to isolate network traffic between tenants. 2.3. Securing the Service Mesh Authorization policies and mTLS allow you to secure Service Mesh. Procedure Make sure that all Red Hat OpenShift Serverless projects of your tenant are part of the same ServiceMeshMemberRoll object as members: apiVersion: maistra.io/v1 kind: ServiceMeshMemberRoll metadata: name: default namespace: istio-system spec: members: - knative-serving # static value, needs to be here, see setup page - knative-eventing # static value, needs to be here, see setup page - team-alpha-1 # example OpenShift project that belongs to the team-alpha tenant - team-alpha-2 # example OpenShift project that belongs th the team-alpha tenant - team-bravo-1 # example OpenShift project that belongs to the team-bravo tenant - team-bravo-2 # example OpenShift project that belongs th the team-bravo tenant All projects that are part of the mesh must enforce mTLS in strict mode. This forces Istio to only accept connections with a client-certificate present and allows the Service Mesh sidecar to validate the origin using an AuthorizationPolicy object. Create the configuration with AuthorizationPolicy objects in the knative-serving and knative-eventing namespaces: Example knative-default-authz-policies.yaml configuration file apiVersion: security.istio.io/v1beta1 kind: AuthorizationPolicy metadata: name: deny-all-by-default namespace: knative-eventing spec: { } --- apiVersion: security.istio.io/v1beta1 kind: AuthorizationPolicy metadata: name: deny-all-by-default namespace: knative-serving spec: { } --- apiVersion: security.istio.io/v1beta1 kind: AuthorizationPolicy metadata: name: allow-mt-channel-based-broker-ingress-to-imc-dispatcher namespace: knative-eventing spec: action: ALLOW selector: matchLabels: app.kubernetes.io/component: "imc-dispatcher" rules: - from: - source: namespaces: [ "knative-eventing" ] principals: [ "cluster.local/ns/knative-eventing/sa/mt-broker-ingress" ] to: - operation: methods: [ "POST" ] --- apiVersion: security.istio.io/v1beta1 kind: AuthorizationPolicy metadata: name: allow-mt-channel-based-broker-ingress-to-kafka-channel namespace: knative-eventing spec: action: ALLOW selector: matchLabels: app.kubernetes.io/component: "kafka-channel-receiver" rules: - from: - source: namespaces: [ "knative-eventing" ] principals: [ "cluster.local/ns/knative-eventing/sa/mt-broker-ingress" ] to: - operation: methods: [ "POST" ] --- apiVersion: security.istio.io/v1beta1 kind: AuthorizationPolicy metadata: name: allow-kafka-channel-to-mt-channel-based-broker-filter namespace: knative-eventing spec: action: ALLOW selector: matchLabels: app.kubernetes.io/component: "broker-filter" rules: - from: - source: namespaces: [ "knative-eventing" ] principals: [ "cluster.local/ns/knative-eventing/sa/knative-kafka-channel-data-plane" ] to: - operation: methods: [ "POST" ] --- apiVersion: security.istio.io/v1beta1 kind: AuthorizationPolicy metadata: name: allow-imc-to-mt-channel-based-broker-filter namespace: knative-eventing spec: action: ALLOW selector: matchLabels: app.kubernetes.io/component: "broker-filter" rules: - from: - source: namespaces: [ "knative-eventing" ] principals: [ "cluster.local/ns/knative-eventing/sa/imc-dispatcher" ] to: - operation: methods: [ "POST" ] --- apiVersion: security.istio.io/v1beta1 kind: AuthorizationPolicy metadata: name: allow-probe-kafka-broker-receiver namespace: knative-eventing spec: action: ALLOW selector: matchLabels: app.kubernetes.io/component: "kafka-broker-receiver" rules: - from: - source: namespaces: [ "knative-eventing" ] principals: [ "cluster.local/ns/knative-eventing/sa/kafka-controller" ] to: - operation: methods: [ "GET" ] --- apiVersion: security.istio.io/v1beta1 kind: AuthorizationPolicy metadata: name: allow-probe-kafka-sink-receiver namespace: knative-eventing spec: action: ALLOW selector: matchLabels: app.kubernetes.io/component: "kafka-sink-receiver" rules: - from: - source: namespaces: [ "knative-eventing" ] principals: [ "cluster.local/ns/knative-eventing/sa/kafka-controller" ] to: - operation: methods: [ "GET" ] --- apiVersion: security.istio.io/v1beta1 kind: AuthorizationPolicy metadata: name: allow-probe-kafka-channel-receiver namespace: knative-eventing spec: action: ALLOW selector: matchLabels: app.kubernetes.io/component: "kafka-channel-receiver" rules: - from: - source: namespaces: [ "knative-eventing" ] principals: [ "cluster.local/ns/knative-eventing/sa/kafka-controller" ] to: - operation: methods: [ "GET" ] --- apiVersion: security.istio.io/v1beta1 kind: AuthorizationPolicy metadata: name: allow-traffic-to-activator namespace: knative-serving spec: selector: matchLabels: app: activator action: ALLOW rules: - from: - source: namespaces: [ "knative-serving", "istio-system" ] --- apiVersion: security.istio.io/v1beta1 kind: AuthorizationPolicy metadata: name: allow-traffic-to-autoscaler namespace: knative-serving spec: selector: matchLabels: app: autoscaler action: ALLOW rules: - from: - source: namespaces: [ "knative-serving" ] These policies restrict the access rules for the network communication between Serverless system components. Specifically, they enforce the following rules: Deny all traffic that is not explicitly allowed in the knative-serving and knative-eventing namespaces Allow traffic from the istio-system and knative-serving namespaces to activator Allow traffic from the knative-serving namespace to autoscaler Allow health probes for Apache Kafka components in the knative-eventing namespace Allow internal traffic for channel-based brokers in the knative-eventing namespace Apply the authorization policy configuration: USD oc apply -f knative-default-authz-policies.yaml Define which OpenShift projects can communicate with each other. For this communication, every OpenShift project of a tenant requires the following: One AuthorizationPolicy object limiting directly incoming traffic to the tenant's project One AuthorizationPolicy object limiting incoming traffic using the activator component of Serverless that runs in the knative-serving project One AuthorizationPolicy object allowing Kubernetes to call PreStopHooks on Knative Services Instead of creating these policies manually, install the helm utility and create the necessary resources for each tenant: Installing the helm utility USD helm repo add openshift-helm-charts https://charts.openshift.io/ Creating example configuration for team alpha USD helm template openshift-helm-charts/redhat-knative-istio-authz --version 1.31.0 --set "name=team-alpha" --set "namespaces={team-alpha-1,team-alpha-2}" > team-alpha.yaml Creating example configuration for team bravo USD helm template openshift-helm-charts/redhat-knative-istio-authz --version 1.31.0 --set "name=team-bravo" --set "namespaces={team-bravo-1,team-bravo-2}" > team-bravo.yaml Apply the authorization policy configuration: USD oc apply -f team-alpha.yaml team-bravo.yaml 2.4. Verifying the configuration You can use the curl command to verify the configuration for network traffic isolation. Note The following examples assume having two tenants, each having one namespace, and all part of the ServiceMeshMemberRoll object, configured with the resources in the team-alpha.yaml and team-bravo.yaml files. Procedure Deploy Knative Services in the namespaces of both of the tenants: Example command for team-alpha USD kn service create test-webapp -n team-alpha-1 \ --annotation-service serving.knative.openshift.io/enablePassthrough=true \ --annotation-revision sidecar.istio.io/inject=true \ --env RESPONSE="Hello Serverless" \ --image docker.io/openshift/hello-openshift Example command for team-bravo USD kn service create test-webapp -n team-bravo-1 \ --annotation-service serving.knative.openshift.io/enablePassthrough=true \ --annotation-revision sidecar.istio.io/inject=true \ --env RESPONSE="Hello Serverless" \ --image docker.io/openshift/hello-openshift Alternatively, use the following YAML configuration: apiVersion: serving.knative.dev/v1 kind: Service metadata: name: test-webapp namespace: team-alpha-1 annotations: serving.knative.openshift.io/enablePassthrough: "true" spec: template: metadata: annotations: sidecar.istio.io/inject: 'true' spec: containers: - image: docker.io/openshift/hello-openshift env: - name: RESPONSE value: "Hello Serverless!" --- apiVersion: serving.knative.dev/v1 kind: Service metadata: name: test-webapp namespace: team-bravo-1 annotations: serving.knative.openshift.io/enablePassthrough: "true" spec: template: metadata: annotations: sidecar.istio.io/inject: 'true' spec: containers: - image: docker.io/openshift/hello-openshift env: - name: RESPONSE value: "Hello Serverless!" Deploy a curl pod for testing the connections: USD cat <<EOF | oc apply -f - apiVersion: apps/v1 kind: Deployment metadata: name: curl namespace: team-alpha-1 labels: app: curl spec: replicas: 1 selector: matchLabels: app: curl template: metadata: labels: app: curl annotations: sidecar.istio.io/inject: 'true' spec: containers: - name: curl image: curlimages/curl command: - sleep - "3600" EOF Verify the configuration by using the curl command. Test team-alpha-1 team-alpha-1 through cluster local domain, which is allowed: Example command USD oc exec deployment/curl -n team-alpha-1 -it -- curl -v http://test-webapp.team-alpha-1:80 Example output HTTP/1.1 200 OK content-length: 18 content-type: text/plain; charset=utf-8 date: Wed, 26 Jul 2023 12:49:59 GMT server: envoy x-envoy-upstream-service-time: 9 Hello Serverless! Test the team-alpha-1 to team-alpha-1 connection through an external domain, which is allowed: Example command USD EXTERNAL_URL=USD(oc get ksvc -n team-alpha-1 test-webapp -o custom-columns=:.status.url --no-headers) && \ oc exec deployment/curl -n team-alpha-1 -it -- curl -ik USDEXTERNAL_URL Example output HTTP/2 200 content-length: 18 content-type: text/plain; charset=utf-8 date: Wed, 26 Jul 2023 12:55:30 GMT server: istio-envoy x-envoy-upstream-service-time: 3629 Hello Serverless! Test the team-alpha-1 to team-bravo-1 connection through the cluster's local domain, which is not allowed: Example command USD oc exec deployment/curl -n team-alpha-1 -it -- curl -v http://test-webapp.team-bravo-1:80 Example output * processing: http://test-webapp.team-bravo-1:80 * Trying 172.30.73.216:80... * Connected to test-webapp.team-bravo-1 (172.30.73.216) port 80 > GET / HTTP/1.1 > Host: test-webapp.team-bravo-1 > User-Agent: curl/8.2.0 > Accept: */* > < HTTP/1.1 403 Forbidden < content-length: 19 < content-type: text/plain < date: Wed, 26 Jul 2023 12:55:49 GMT < server: envoy < x-envoy-upstream-service-time: 6 < * Connection #0 to host test-webapp.team-bravo-1 left intact RBAC: access denied Test the team-alpha-1 to team-bravo-1 connection through an external domain, which is allowed: Example command USD EXTERNAL_URL=USD(oc get ksvc -n team-bravo-1 test-webapp -o custom-columns=:.status.url --no-headers) && \ oc exec deployment/curl -n team-alpha-1 -it -- curl -ik USDEXTERNAL_URL Example output HTTP/2 200 content-length: 18 content-type: text/plain; charset=utf-8 date: Wed, 26 Jul 2023 12:56:22 GMT server: istio-envoy x-envoy-upstream-service-time: 2856 Hello Serverless! Delete the resources that were created for verification: USD oc delete deployment/curl -n team-alpha-1 && \ oc delete ksvc/test-webapp -n team-alpha-1 && \ oc delete ksvc/test-webapp -n team-bravo-1 Additional resources for OpenShift Container Platform The Helm utility Option reference for the Helm utility

Commands:
apiVersion: maistra.io/v1 kind: ServiceMeshMemberRoll metadata: name: default namespace: istio-system spec: members: - knative-serving # static value, needs to be here, see setup page - knative-eventing # static value, needs to be here, see setup page - team-alpha-1 # example OpenShift project that belongs to the team-alpha tenant - team-alpha-2 # example OpenShift project that belongs th the team-alpha tenant - team-bravo-1 # example OpenShift project that belongs to the team-bravo tenant - team-bravo-2 # example OpenShift project that belongs th the team-bravo tenant
apiVersion: security.istio.io/v1beta1 kind: AuthorizationPolicy metadata: name: deny-all-by-default namespace: knative-eventing spec: { } --- apiVersion: security.istio.io/v1beta1 kind: AuthorizationPolicy metadata: name: deny-all-by-default namespace: knative-serving spec: { } --- apiVersion: security.istio.io/v1beta1 kind: AuthorizationPolicy metadata: name: allow-mt-channel-based-broker-ingress-to-imc-dispatcher namespace: knative-eventing spec: action: ALLOW selector: matchLabels: app.kubernetes.io/component: "imc-dispatcher" rules: - from: - source: namespaces: [ "knative-eventing" ] principals: [ "cluster.local/ns/knative-eventing/sa/mt-broker-ingress" ] to: - operation: methods: [ "POST" ] --- apiVersion: security.istio.io/v1beta1 kind: AuthorizationPolicy metadata: name: allow-mt-channel-based-broker-ingress-to-kafka-channel namespace: knative-eventing spec: action: ALLOW selector: matchLabels: app.kubernetes.io/component: "kafka-channel-receiver" rules: - from: - source: namespaces: [ "knative-eventing" ] principals: [ "cluster.local/ns/knative-eventing/sa/mt-broker-ingress" ] to: - operation: methods: [ "POST" ] --- apiVersion: security.istio.io/v1beta1 kind: AuthorizationPolicy metadata: name: allow-kafka-channel-to-mt-channel-based-broker-filter namespace: knative-eventing spec: action: ALLOW selector: matchLabels: app.kubernetes.io/component: "broker-filter" rules: - from: - source: namespaces: [ "knative-eventing" ] principals: [ "cluster.local/ns/knative-eventing/sa/knative-kafka-channel-data-plane" ] to: - operation: methods: [ "POST" ] --- apiVersion: security.istio.io/v1beta1 kind: AuthorizationPolicy metadata: name: allow-imc-to-mt-channel-based-broker-filter namespace: knative-eventing spec: action: ALLOW selector: matchLabels: app.kubernetes.io/component: "broker-filter" rules: - from: - source: namespaces: [ "knative-eventing" ] principals: [ "cluster.local/ns/knative-eventing/sa/imc-dispatcher" ] to: - operation: methods: [ "POST" ] --- apiVersion: security.istio.io/v1beta1 kind: AuthorizationPolicy metadata: name: allow-probe-kafka-broker-receiver namespace: knative-eventing spec: action: ALLOW selector: matchLabels: app.kubernetes.io/component: "kafka-broker-receiver" rules: - from: - source: namespaces: [ "knative-eventing" ] principals: [ "cluster.local/ns/knative-eventing/sa/kafka-controller" ] to: - operation: methods: [ "GET" ] --- apiVersion: security.istio.io/v1beta1 kind: AuthorizationPolicy metadata: name: allow-probe-kafka-sink-receiver namespace: knative-eventing spec: action: ALLOW selector: matchLabels: app.kubernetes.io/component: "kafka-sink-receiver" rules: - from: - source: namespaces: [ "knative-eventing" ] principals: [ "cluster.local/ns/knative-eventing/sa/kafka-controller" ] to: - operation: methods: [ "GET" ] --- apiVersion: security.istio.io/v1beta1 kind: AuthorizationPolicy metadata: name: allow-probe-kafka-channel-receiver namespace: knative-eventing spec: action: ALLOW selector: matchLabels: app.kubernetes.io/component: "kafka-channel-receiver" rules: - from: - source: namespaces: [ "knative-eventing" ] principals: [ "cluster.local/ns/knative-eventing/sa/kafka-controller" ] to: - operation: methods: [ "GET" ] --- apiVersion: security.istio.io/v1beta1 kind: AuthorizationPolicy metadata: name: allow-traffic-to-activator namespace: knative-serving spec: selector: matchLabels: app: activator action: ALLOW rules: - from: - source: namespaces: [ "knative-serving", "istio-system" ] --- apiVersion: security.istio.io/v1beta1 kind: AuthorizationPolicy metadata: name: allow-traffic-to-autoscaler namespace: knative-serving spec: selector: matchLabels: app: autoscaler action: ALLOW rules: - from: - source: namespaces: [ "knative-serving" ]
oc apply -f knative-default-authz-policies.yaml
helm repo add openshift-helm-charts https://charts.openshift.io/
helm template openshift-helm-charts/redhat-knative-istio-authz --version 1.31.0 --set "name=team-alpha" --set "namespaces={team-alpha-1,team-alpha-2}" > team-alpha.yaml
helm template openshift-helm-charts/redhat-knative-istio-authz --version 1.31.0 --set "name=team-bravo" --set "namespaces={team-bravo-1,team-bravo-2}" > team-bravo.yaml
oc apply -f team-alpha.yaml team-bravo.yaml
kn service create test-webapp -n team-alpha-1 --annotation-service serving.knative.openshift.io/enablePassthrough=true --annotation-revision sidecar.istio.io/inject=true --env RESPONSE="Hello Serverless" --image docker.io/openshift/hello-openshift
kn service create test-webapp -n team-bravo-1 --annotation-service serving.knative.openshift.io/enablePassthrough=true --annotation-revision sidecar.istio.io/inject=true --env RESPONSE="Hello Serverless" --image docker.io/openshift/hello-openshift
apiVersion: serving.knative.dev/v1 kind: Service metadata: name: test-webapp namespace: team-alpha-1 annotations: serving.knative.openshift.io/enablePassthrough: "true" spec: template: metadata: annotations: sidecar.istio.io/inject: 'true' spec: containers: - image: docker.io/openshift/hello-openshift env: - name: RESPONSE value: "Hello Serverless!" --- apiVersion: serving.knative.dev/v1 kind: Service metadata: name: test-webapp namespace: team-bravo-1 annotations: serving.knative.openshift.io/enablePassthrough: "true" spec: template: metadata: annotations: sidecar.istio.io/inject: 'true' spec: containers: - image: docker.io/openshift/hello-openshift env: - name: RESPONSE value: "Hello Serverless!"
cat <<EOF | oc apply -f - apiVersion: apps/v1 kind: Deployment metadata: name: curl namespace: team-alpha-1 labels: app: curl spec: replicas: 1 selector: matchLabels: app: curl template: metadata: labels: app: curl annotations: sidecar.istio.io/inject: 'true' spec: containers: - name: curl image: curlimages/curl command: - sleep - "3600" EOF
oc exec deployment/curl -n team-alpha-1 -it -- curl -v http://test-webapp.team-alpha-1:80
HTTP/1.1 200 OK content-length: 18 content-type: text/plain; charset=utf-8 date: Wed, 26 Jul 2023 12:49:59 GMT server: envoy x-envoy-upstream-service-time: 9 Hello Serverless!
EXTERNAL_URL=USD(oc get ksvc -n team-alpha-1 test-webapp -o custom-columns=:.status.url --no-headers) && exec deployment/curl -n team-alpha-1 -it -- curl -ik USDEXTERNAL_URL
HTTP/2 200 content-length: 18 content-type: text/plain; charset=utf-8 date: Wed, 26 Jul 2023 12:55:30 GMT server: istio-envoy x-envoy-upstream-service-time: 3629 Hello Serverless!
oc exec deployment/curl -n team-alpha-1 -it -- curl -v http://test-webapp.team-bravo-1:80
* processing: http://test-webapp.team-bravo-1:80 * Trying 172.30.73.216:80 * Connected to test-webapp.team-bravo-1 (172.30.73.216) port 80 > GET / HTTP/1.1 > Host: test-webapp.team-bravo-1 > User-Agent: curl/8.2.0 > Accept: */* > < HTTP/1.1 403 Forbidden < content-length: 19 < content-type: text/plain < date: Wed, 26 Jul 2023 12:55:49 GMT < server: envoy < x-envoy-upstream-service-time: 6 < * Connection #0 to host test-webapp.team-bravo-1 left intact RBAC: access denied
EXTERNAL_URL=USD(oc get ksvc -n team-bravo-1 test-webapp -o custom-columns=:.status.url --no-headers) && exec deployment/curl -n team-alpha-1 -it -- curl -ik USDEXTERNAL_URL
HTTP/2 200 content-length: 18 content-type: text/plain; charset=utf-8 date: Wed, 26 Jul 2023 12:56:22 GMT server: istio-envoy x-envoy-upstream-service-time: 2856 Hello Serverless!
oc delete deployment/curl -n team-alpha-1 && delete ksvc/test-webapp -n team-alpha-1 && delete ksvc/test-webapp -n team-bravo-1