Serverless Operator running in Knative

This project demonstrates how to implement CustomResourceDefinition (CRD) controllers using the Knative API server event source feeding Knative services.

This is a Knative variant of the sample controller project.

Prerequisites

• A Kubernetes cluster with Knative 0.6.0
• envsubst installed locally. This is installed by the gettext package. If not installed it can be installed by a Linux package manager, or by Homebrew on OS X.

Running

1. Clone this repository somewhere not under $GOPATH
2. Set $DOCKER_USER
3. Build and publish the sample-controller docker image

go get ./...
CGO_ENABLED=0 GOOS=linux go build -o sample-controller cmd/reconcile/main.go
docker build -t $DOCKER_USER/sample-controller .
docker push $DOCKER_USER/sample-controller

4. Deploy the sample controller in the default namespace:

envsubst < config/template/ksvc-example.yaml | kubectl apply -f -
kubectl apply -Rf config/default

Two pods are created: one watching for events (apiserver-example-foo-XXX) and another one containing the reconciling loop (example-foo-reconcile-XXX-deployment-YYY-ZZZ). The first pod always stays alive, whereas the second one scale down to zero when there is no events.

Verifying

1. In one terminal, watch for pods.

watch kubectl get pods

2. In another terminal, create a Foo object:

kubectl apply -f sample

Observe the pod named example-foo-reconcile-XXX being created.

3. Check the controller for Foo is working:

kubectl get deployments example-foo
NAME          DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
example-foo   1         1         1            1           4m48s

Observe the pod named example-foo-reconcile-XXX being deleted after about 1mn30s (default Knative scale down period).

Cleaning

1. Delete the sample

kubectl delete -f sample/

2. Delete the controller:

kubectl delete -Rf config