Build Your Operator with the Right Tool!

This repository presents a tutorial to build a basic sample operator using different techniques.

What You'll Build

Our Operator is responsible for creating a Hazelcast cluster from the following resource definition hazelcast.yaml:

apiVersion: hazelcast.my.domain/v1
kind: Hazelcast
metadata:
  name: hazelcast-sample
spec:
  size: 1

The only parameter to configure is size which decides on the number of running Hazelcast Pods.

All other parameters are hardcoded, for example, Hazelcast Docker: hazelcast/hazelcast:4.1.

How You'll Build

No matter of the operator type, you'll always proceed with the steps below. Note that only the first point differs between different ways of creating operators.

1. Create operator (using different techniques)
2. Dockerize operator application and push it into Docker Hub

docker build -t <username>/hazelcast-operator:<type> . && docker push <username>/hazelcast-operator:<type>

3. Create Hazelcast CRD (Custom Role Definition) and RBAC (Cluster Role and Cluster Role Binding)

kubectl apply -f hazelcast.crd.yaml
kubectl apply -f role.yaml
kubectl apply -f role_binding.yaml

4. Deploy an operator

kubectl apply -f operator.yaml

5. Create Hazelcast Resource

kubectl apply -f hazelcast.yaml

Operator Tools & Techniques

• Operator SDK: Helm - Generate Operator from a Helm Chart
• Operator SDK: Ansible - Create Operator using Ansible
• Operator SDK: Go - Write Operator in Go language using Operator SDK
• KOPF (Kubernetes Operator Pythonic Framework) - Write Operator with KOPF using Python
• Java - Write Operator with Java (and Quarkus for Docker native builds)