k8soperator

A sample K8S Operator to demonstrate crud app deployment

Getting Started

You’ll need a Kubernetes cluster to run against. You can use KIND to get a local cluster for testing, or run against a remote cluster. Note: Your controller will automatically use the current context in your kubeconfig file (i.e. whatever cluster kubectl cluster-info shows).

User Path

Testing has been done on local kind cluster

Deploy operator

# clone operator repo
git clone https://github.com/techierishi/k8soperator.git
cd k8soperator

# deploy to local cluster
helm install -f chart/values.yaml crud-helm ./chart/

# now create Crud kind
./bin/kustomize build config/samples | kubectl apply -f -

Port forward

kubectl port-forward svc/mongocrud 8060:8060

Get all resources:

kubectl get sc; kubectl get pv; kubectl get pvc; kubectl get pod; kubectl get service

Delete all created resources:

./bin/kustomize build config/samples | kubectl delete -f -; kubectl delete sc crud-storage-class; kubectl delete pv crud-pv

Code explanation

internal/controller/crud_controller.go is the entrypoint of all reconcilers internal/controller/storage_class.go is to create storage class with AllowVolumeExpansion capability internal/controller/pc.go is to create persistent volume internal/controller/pvc.go is to create persistent volume claim for database internal/controller/service.go is to create node port service internal/controller/deployment.go is to create deployment config/samples/schedule_v1_crud.yaml has sample Crud kind yaml

Developer Path

Running on the cluster

Install Instances of Custom Resources:

kubectl apply -f config/samples/

Build and push your image to the location specified by IMG:

make docker-build docker-push IMG=ghcr.io/techierishi/k8soperator:latest

Deploy the controller to the cluster with the image specified by IMG:

make deploy IMG=ghcr.io/techierishi/k8soperator:latest

Uninstall CRDs

To delete the CRDs from the cluster:

make uninstall

Undeploy controller

UnDeploy the controller from the cluster:

make undeploy

Contributing

https://github.com/techierishi

How it works

This project aims to follow the Kubernetes Operator pattern.

It uses Controllers, which provide a reconcile function responsible for synchronizing resources until the desired state is reached on the cluster.

Test It Out

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

NOTE: You can also run this in one step by running: make install run

Modifying the API definitions

If you are editing the API definitions, generate the manifests such as CRs or CRDs using:

make manifests

NOTE: Run make --help for more information on all potential make targets

More information can be found via the Kubebuilder Documentation

Bundle commands

make bundle IMG=ghcr.io/techierishi/k8soperator:latest
make bundle-build BUNDLE_IMG=ghcr.io/techierishi/k8soperator-bundle:latest
make docker-push IMG=ghcr.io/techierishi/k8soperator-bundle:latest

Generate helm charts

make helm

Caveats

Some cluster role has too much of permission make sure operator has enough role. This should be avoided in prod
Best coding practices may be missing at some places keeping the mind that this is a test app

License

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.