Creating an ApiServerSource object¶

This topic describes how to create an ApiServerSource object.

Before you begin¶

Before you can create an ApiServerSource object:

You must have Knative Eventing installed on your cluster.
You must install the kubectl CLI tool.
Optional: If you want to use the kn commands, install the kn tool.

Create an ApiServerSource object¶

Optional: Create a namespace for the API server source instance by running the command:
```
kubectl create namespace <namespace>
```
Where <namespace> is the name of the namespace that you want to create.

Note

Creating a namespace for your ApiServerSource and related components allows you to view changes and events for this workflow more easily, since these are isolated from the many other components that may exist in your default namespace.

It also makes removing the source easier, since you can simply delete the namespace to remove all of the resources.
Create a ServiceAccount:
1. Create a YAML file using the following template:
```
apiVersion: v1
kind: ServiceAccount
metadata:
  name: <service-account>
  namespace: <namespace>
```
  Where:
  - <service-account> is the name of the ServiceAccount that you want to create.
  - <namespace> is the namespace that you created in step 1 earlier.
2. Apply the YAML file by running the command:
```
kubectl apply -f <filename>.yaml
```
  Where <filename> is the name of the file you created in the previous step.
Create a ClusterRole:
1. Create a YAML file using the following template:
```
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: <cluster-role>
rules:
- apiGroups:
  - ""
  resources:
  - events
  verbs:
  - get
  - list
  - watch
```
  Where <cluster-role> is the name of the ClusterRole that you want to create.
2. Apply the YAML file by running the command:
```
kubectl apply -f <filename>.yaml
```
  Where <filename> is the name of the file you created in the previous step.
Create a ClusterRoleBinding:
1. Create a YAML file using the following template:
```
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: <cluster-role-binding>
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: <cluster-role>
subjects:
- kind: ServiceAccount
  name: <service-account>
  namespace: <namespace>
```
  Where:
  - <cluster-role-binding> is the name of the ClusterRoleBinding that you want to create.
  - <cluster-role> is the name of the ClusterRole that you created in step 3 earlier.
  - <service-account> is the name of the ServiceAccount that you created in step 2 earlier.
  - <namespace> is the name of the namespace that you created in step 1 earlier.
2. Apply the YAML file by running the command:
```
kubectl apply -f <filename>.yaml
```
  Where <filename> is the name of the file you created in the previous step.
Create the ApiServerSource object:
kn
- To create the ApiServerSource, run the command:
  kn source apiserver create <apiserversource> \ --namespace <namespace> \ --mode "Resource" \ --resource "Event:v1" \ --service-account <service-account> \ --sink <sink>
  Where:
  - <apiserversource> is the name of the source that you want to create.
  - <namespace> is the name of the namespace that you created in step 1 earlier.
  - <service-account> is the name of the ServiceAccount that you created in step 2 earlier.
  - <sink> is the name of the PodSpecable object that you want to use as a sink. A PodSpecable is an object that describes a PodSpec.
YAML
1. Create a YAML file using the following template:
  apiVersion: sources.knative.dev/v1 kind: ApiServerSource metadata: name: <apiserversource> namespace: <namespace> spec: serviceAccountName: <service-account> mode: <event-mode> resources: - apiVersion: v1 kind: Event sink: ref: apiVersion: v1 kind: <sink-kind> name: <sink-name>
  Where:
  - <apiserversource> is the name of the source that you want to create.
  - <namespace> is the name of the namespace that you created in step 1 earlier.
  - <service-account> is the name of the ServiceAccount that you created in step 2 earlier.
  - <event-mode> is either Resource or Reference. If set to Resource, the event payload contains the entire resource that the event is for. If set to Reference, the event payload only contains a reference to the resource that the event is for. The default is Reference.
  - <sink-kind> is any supported PodSpecable object that you want to use as a sink, for example, Service or Deployment. A PodSpecable is an object that describes a PodSpec.
  - <sink-name> is the name of your sink.
2. Apply the YAML file by running the command:
  kubectl apply -f <filename>.yaml
  Where <filename> is the name of the file you created in the previous step.

Verify the ApiServerSource object¶

Make the Kubernetes API server create events by launching a test pod in your namespace by running the command:
```
kubectl run busybox --image=busybox --namespace=<namespace> --restart=Never -- ls
```
Where <namespace> is the name of the namespace that you created in step 1 earlier.
Delete the test pod by running the command:
```
kubectl --namespace=<namespace> delete pod busybox
```
Where <namespace> is the name of the namespace that you created in step 1 earlier.

View the logs to verify that Kubernetes events were sent to the sink by the Knative Eventing system by running the command:

kubectl logs --namespace=<namespace> -l app=<sink> --tail=100

Where:

<namespace> is the name of the namespace that you created in step 1 earlier.
<sink> is the name of the PodSpecable object that you used as a sink in step 5 earlier.

Example log output:

☁️  cloudevents.Event
Validation: valid
Context Attributes,
  specversion: 1.0
  type: dev.knative.apiserver.resource.update
  source: https://10.96.0.1:443
  subject: /apis/v1/namespaces/apiserversource-example/events/testevents.15dd3050eb1e6f50
  id: e0447eb7-36b5-443b-9d37-faf4fe5c62f0
  time: 2020-07-28T19:14:54.719501054Z
  datacontenttype: application/json
Extensions,
  kind: Event
  name: busybox.1626008649e617e3
  namespace: apiserversource-example
Data,
  {
    "apiVersion": "v1",
    "count": 1,
    "eventTime": null,
    "firstTimestamp": "2020-07-28T19:14:54Z",
    "involvedObject": {
      "apiVersion": "v1",
      "fieldPath": "spec.containers{busybox}",
      "kind": "Pod",
      "name": "busybox",
      "namespace": "apiserversource-example",
      "resourceVersion": "28987493",
      "uid": "1efb342a-737b-11e9-a6c5-42010a8a00ed"
    },
    "kind": "Event",
    "lastTimestamp": "2020-07-28T19:14:54Z",
    "message": "Started container",
    "metadata": {
      "creationTimestamp": "2020-07-28T19:14:54Z",
      "name": "busybox.1626008649e617e3",
      "namespace": "default",
      "resourceVersion": "506088",
    "selfLink": "/api/v1/namespaces/apiserversource-example/events/busybox.1626008649e617e3",
      "uid": "2005af47-737b-11e9-a6c5-42010a8a00ed"
    },
    "reason": "Started",
    "reportingComponent": "",
    "reportingInstance": "",
    "source": {
      "component": "kubelet",
      "host": "gke-knative-auto-cluster-default-pool-23c23c4f-xdj0"
    },
    "type": "Normal"
  }

Delete the ApiServerSource¶

To remove the ApiServerSource object and all of the related resources:

Delete the namespace by running the command:
```
kubectl delete namespace <namespace>
```
Where <namespace> is the name of the namespace that you created in step 1 earlier.