apiserversource-yaml.adoc

Using the API server source with the YAML method

This guide describes the steps required to create an API server source 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 API server source YAML file.

Procedure

1. Create a service account, role, and role binding for the API server source as a YAML file:

   Note	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.

   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 the API server source.

2. Apply the YAML file:

   $ oc apply -f <filename>

3. 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

4. Apply the ApiServerSource YAML file:

   $ oc apply -f <filename>

5. 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

6. Apply the Service YAML file:

   $ oc apply -f <filename>

7. Create a Trigger object as a YAML file that filters events from the default broker to the service created in the previous 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

8. Apply the Trigger YAML file:

   $ oc apply -f <filename>

9. Create events by launching a pod in the default namespace:

   $ oc create deployment hello-node --image=quay.io/openshift-knative/knative-eventing-sources-event-display

10. 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

    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.

1. Get the pods by entering the following command:

   $ oc get pods

2. View the message dumper function logs for the pods by entering the following command:

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

   Example output

   ☁️  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",
       ...
     }