another-replicaset-operator

README

Another ReplicaSet Controller/Operator

The objective is to implement a replicaset controller similar to Kube replicaset controller using kubebuilder quick start. The process of implementating a controller will help the developer better understanding the challenges and understanding of how Kubernetes controllers work.

Steps to generate this project

$ go mod init another-replicaset-operator

$ kubebuilder version
  Version: main.version{KubeBuilderVersion:"3.1.0", KubernetesVendor:"1.19.2", GitCommit:"92e0349ca7334a0a8e5e499da4fb077eb524e94a", BuildDate:"2021-05-27T17:54:28Z", GoOs:"linux", GoArch:"amd64"}

$ kubebuilder init --domain my.domain
$ kubebuilder create api --group replicaset --version v1alpha1 --kind AnotherReplicaSet

Steps after changing the API

• If you are editing the API definitions, generate the manifests such as Custom Resources (CRs) or Custom Resource Defintions (CRDs) using

make manifests

Steps to run the operator

• Before running the operator , check if the api group already exists

kubectl api-resources --api-group=replicaset.my.domain

• Install the CRDs into the cluster:

make install

• Run your controller (this will run in the foreground, so switch to a new terminal if you want to leave it running)

make run

• Check the api-resources (optional)

$ kubectl api-resources --api-group=replicaset.my.domain
NAME                 SHORTNAMES   APIVERSION                      NAMESPACED   KIND
anotherreplicasets                replicaset.my.domain/v1alpha1   true         AnotherReplicaSet

Steps to test the operator

• Apply the custom resource in another terminal which has KUBECONFIG configured for the kube environment

  kubectl apply -f manifests/busybox/busybox-another-replicaset.yaml --validate=false

Uninstall CRDs

• To delete your CRDs from the cluster

make uninstall

Undeploy controller

• Undeploy the controller to the cluster

make undeploy