docs/eventing/samples/kubernetes-event-source

Kubernetes Event Source example

Kubernetes Event Source example shows how to wire kubernetes cluster events for consumption by a function that has been implemented as a Knative Service.

Deployment Steps

Prerequisites

1. Setup Knative Eventing.
2. Install Knative Eventing Sources.
3. Install the in-memory ClusterChannelProvisioner.
   • Note that you can skip this if you choose to use a different type of Channel. If so, you will need to modify channel.yaml before deploying it.
4. Create a Channel. You can use your own Channel or use the provided sample, which creates a channel called testchannel. If you use your own Channel with a different name, then you will need to alter other commands later.

kubectl -n default apply -f eventing/samples/kubernetes-event-source/channel.yaml

Service Account

1. Create a Service Account that the Receive Adapter runs as. The Receive Adapater watches for Kubernetes events and forwards them to the Knative Eventing Framework. If you want to re-use an existing Service Account with the appropriate permissions, you need to modify the

kubectl apply -f eventing/samples/kubernetes-event-source/serviceaccount.yaml

Deploy Event Sources

1. Deploy the KubernetesEventSource controller as part of eventing-source's controller. This makes kubernetes events available for subscriptions.

ko apply -f config/default.yaml

Create Event Source for Kubernetes Events

1. In order to receive events, you have to create a concrete Event Source for a specific namespace. If you are wanting to consume events from a differenet namespace or using a different Service Account, you need to modify the yaml accordingly.

kubectl apply -f eventing/samples/kubernetes-event-source/k8s-events.yaml

Subscriber

In order to check the KubernetesEventSource is fully working, we will create a simple Knative Service that dumps incoming messages to its log and create a Subscription from the Channel to that Knative Service.

1. Setup Knative Serving.
2. If the deployed KubernetesEventSource is pointing at a Channel other than testchannel, modify subscription.yaml by replacing testchannel with that Channel's name.
3. Deploy subscription.yaml.

ko apply -f eventing/samples/kubernetes-event-source/subscription.yaml

Create Events

Create events by launching a pod in the default namespace. Create a busybox container

kubectl run -i --tty busybox --image=busybox --restart=Never -- sh

Once the shell comes up, just exit it and kill the pod.

kubectl delete pods busybox

Verify

We will verify that the kubernetes events were sent into the Knative eventing system by looking at our message dumper function logsIf you deployed the Subscriber, then continue using this section. If not, then you will need to look downstream yourself.

kubectl get pods
kubectl logs message-dumper-XXXX user-container

You should see log lines similar to:

{"metadata":{"name":"busybox.15644359eaa4d8e7","namespace":"default","selfLink":"/api/v1/namespaces/default/events/busybox.15644359eaa4d8e7","uid":"daf8d3ca-e10d-11e8-bf3c-42010a8a017d","resourceVersion":"7840","creationTimestamp":"2018-11-05T15:17:05Z"},"involvedObject":{"kind":"Pod","namespace":"default","name":"busybox","uid":"daf645df-e10d-11e8-bf3c-42010a8a017d","apiVersion":"v1","resourceVersion":"681388"},"reason":"Scheduled","message":"Successfully assigned busybox to gke-knative-eventing-e2e-default-pool-575bcad9-vz55","source":{"component":"default-scheduler"},"firstTimestamp":"2018-11-05T15:17:05Z","lastTimestamp":"2018-11-05T15:17:05Z","count":1,"type":"Normal","eventTime":null,"reportingComponent":"","reportingInstance":""}
Ce-Source: /apis/v1/namespaces/default/pods/busybox
{"metadata":{"name":"busybox.15644359f59f72f2","namespace":"default","selfLink":"/api/v1/namespaces/default/events/busybox.15644359f59f72f2","uid":"db14ff23-e10d-11e8-bf3c-42010a8a017d","resourceVersion":"7841","creationTimestamp":"2018-11-05T15:17:06Z"},"involvedObject":{"kind":"Pod","namespace":"default","name":"busybox","uid":"daf645df-e10d-11e8-bf3c-42010a8a017d","apiVersion":"v1","resourceVersion":"681389"},"reason":"SuccessfulMountVolume","message":"MountVolume.SetUp succeeded for volume \"default-token-pzr6x\" ","source":{"component":"kubelet","host":"gke-knative-eventing-e2e-default-pool-575bcad9-vz55"},"firstTimestamp":"2018-11-05T15:17:06Z","lastTimestamp":"2018-11-05T15:17:06Z","count":1,"type":"Normal","eventTime":null,"reportingComponent":"","reportingInstance":""}
Ce-Source: /apis/v1/namespaces/default/pods/busybox