kubernetes-java-operator-sample

Sample operators leveraging Kubernetes Java Client.

Requirements

Project uses the following tools:

skaffold: to automate test environment setup.
kind: to create local K8s clusters for demo and testing.
kustomize: optional, only required for manual deployment.
Gradle Wrapper: embedded version of gradle (no need to install anything) for project building and test execution.
Java JDK v11

With Kubernetes Java Client

Deployment

The easiest way to get started is with skaffold. If you don't have a K8s cluster already, create a local one with kind.

skaffold run # build and deploy and forget
skaffold delete # delete everything deployed with `skaffold run`

If you'd like to ask skaffold to watch changes and rebuild or redeploy, you may run:

skaffold dev # watch changes and automatically update deployment, tear down when stop the process.

If you want to skip image building and just deploy this sample operator to your cluster, you may run:

kubectl apply -f crds/adoption-center-custom-resource-definition.yaml
kubectl apply -f crds/cat-custom-resource-definition.yaml
kustomize build manifests | kubectl apply -f -

The operator resources will all be deployed to namespace adoption-operator as specified in manifests/operator-namespace.yaml.

Try it out

You may apply a test adoption center and see an adoption center deployment shows up in the operator namespace adoption-operator with the name specified in manifests/test-adoption-center.yaml:

kubectl apply -f manifests/test-adoption-center.yaml
kubectl get deployments -n adoption-operator
kubectl port-forward deployment.apps/kittens-dream-land 8080:8080

Then you can pull the /animals endpoint from the adoption center:

curl localhost:8080/animals # Should receive `[]` without applying a cat resource.

You may apply a test cat resource and see the cat show up in the adoption center /animals endpoint:

kubectl apply -f manifests/test-cat.yaml
kubectl -n adoption-operator wait --for=condition=ready pod/kittens-dream-land-${randomGeneratedHash}
curl localhost:8080/animals # Should see the new cat in the response

Generating Java Classes from CRD

./crds/generate-models-for-crd.sh

This script applies the CRDs to a kubernetes cluster, pulls the openapi endpoint of the API server, and generate classes based on the result there.

More information about the generator module can be found here.

Run tests

To run the Component tests, it's better to use a local development cluster. In this example we are using kind:

kind create cluster
./gradlew test

File Structure

You will notice the following directory structure

├── README.md
├── skaffold.yaml
├── crds
│   ├── adoption-center-custom-resource-definition.yaml
│   ├── cat-custom-resource-definition.yaml
│   └── generate-models-for-crd.sh
├── manifests
│   ├── kustomization.yaml
│   ├── operator-*.yaml
│   ├── test-adoption-center.yaml
│   └── test-cat.yaml
├── with-kubernetes-java-client
│   ├── build.gradle.kts
│   └── src
│       └── ...
└── adoption-center
    ├── build.gradle.kts
    └── src
        └── ...

waqasdilawar / kubernetes-java-operator-sample