A Kubernetes Controller with Spring
A really simple controller that compiles as a native image with GraalVM.
Set Up
Prerequisite: you need a Kubernetes cluster, so kubectl get all has to be working.
Start a config server in the cluster:
kubectl apply -f src/test/k8s/configserver.yaml
and expose it via a port forward:
kubectl port-forward svc/configserver 8888:80
Install CRDs
kubectl apply -f src/main/k8s/crds/configclient.yaml
Create a resource instance:
kubectl apply -f src/test/k8s/debug.yaml
Build and Run
Then you can move on to the controller.
./mvnw spring-boot:run
Verify that it works:
kubectl get configmaps
output:
NAME DATA AGE
demo 4 84m
If you delete the owning resource, the config map is also deleted:
kubectl delete -f src/test/k8s/debug.yaml
kubectl get configmaps
output:
No resources found in default namespace.
There is an integration test which is diabled on the command line by default. If there is a Kubernetes cluster available, you can run it from the IDE, or you can run on the command line with ./mvnw verify -D skip-its=false.
Native Image
Build and extract a native image:
./mvnw spring-boot:build-image
id=$(docker create spring-controller:0.0.1-SNAPSHOT)
docker cp $id:/workspace/io.kubernetes.client.examples.SpringControllerExample target/app
docker rm -v $id > /dev/null
Run it:
./target/app
The above incantation won't work if you're not using Linux, so run the controller within the Docker image. It'll need your Kubernetes configuration file, which you make available to the container.
./mvnw spring-boot:build-image
id=$(docker images -aq spring-controller )
docker run -v $HOME/.kube/:/home/cnb/.kube $id