apiserversource-yaml.adoc

Using the ApiServerSource with the YAML method

This guide describes the steps required to create, manage, and delete an ApiServerSource using YAML files.

Prerequisites

• You will need to have a Knative Serving and Eventing installation.

• You will need to have created the default broker in the same namespace as the one defined in the ApiServerSource YAML file.

Procedure

1. Create a service account, role, and role binding for the ApiServerSource.

   You can do this by creating a file named authentication.yaml and copying the following sample code into it:

   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 (1)
   rules:
     - apiGroups:
         - ""
       resources:
         - events
       verbs:
         - get
         - list
         - watch
   
   ---
   apiVersion: rbac.authorization.k8s.io/v1
   kind: RoleBinding
   metadata:
     name: k8s-ra-event-watcher
     namespace: default (1)
   roleRef:
     apiGroup: rbac.authorization.k8s.io
     kind: Role
     name: event-watcher
   subjects:
     - kind: ServiceAccount
       name: events-sa
       namespace: default (1)

   1. Change this namespace to the namespace that you have selected for installing ApiServerSource.

      Note	If you want to re-use an existing service account with the appropriate permissions, you must modify the authentication.yaml for that service account.

      After you have created the authentication.yaml file, apply it by entering the following command:

      $ oc apply --filename authentication.yaml

2. Create an ApiServerSource event source.

   You can do this by creating a file named k8s-events.yaml and copying the following sample code into it:

   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/v1beta1
         kind: Broker
         name: default

   After you have created the k8s-events.yaml file, apply it by entering the following command:

   $ oc apply --filename k8s-events.yaml

3. To check that the ApiServerSource is set up correctly, create a Knative service that dumps incoming messages to its log.

   Copy the following sample YAML into a file named service.yaml:

   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:v0.13.2

   After you have created the service.yaml file, apply it by entering the following command:

   $ oc apply --filename service.yaml

4. Create a trigger from the default broker to filter events to the service created in the previous step.

   You can create the trigger by creating a file named trigger.yaml and copying the following sample code into it:

   apiVersion: eventing.knative.dev/v1alpha1
   kind: Trigger
   metadata:
     name: event-display-trigger
     namespace: default
   spec:
     subscriber:
       ref:
         apiVersion: serving.knative.dev/v1
         kind: Service
         name: event-display

   After you have created the trigger.yaml file, apply it by entering the following command:

   $ oc apply --filename trigger.yaml

5. Create events by launching a pod in the default namespace. You can do this by entering the following command:

   $ oc create deployment hello-node --image=gcr.io/hello-minikube-zero-install/hello-node

6. Check that the controller is mapped correctly by entering the following command and inspecting the output:

   $ oc get apiserversource.sources.knative.dev testevents -o yaml

   The output should be similar to:

   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/v1beta1
         kind: Broker
         name: default

Verification steps

You can verify that the Kubernetes events were sent into the Knative eventing system by looking at the message dumper function logs.

You can view the message dumper function logs by entering the following commands:

$ oc get pods
$ oc logs $(oc get pod -o name | grep event-display) -c user-container

The logs should contain lines similar to the following:

☁️  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 ApiServerSource

You can delete the ApiServerSource, trigger, service, service account, cluster role, and cluster binding created in this guide by entering the following oc commands:

$ oc delete --filename trigger.yaml
$ oc delete --filename service.yaml
$ oc delete --filename k8s-events.yaml
$ oc delete --filename authentication.yaml