A Guide to Creating Kubernetes Operators with Go
Kubernetes operators are custom software extensions that manage and automate tasks for applications running on Kubernetes clusters. This article demonstrates creating a Kubernetes operator using the Go programming language and the Kubernetes Operator SDK.
To follow this guide, you need:
- A basic understanding of Kubernetes and Go programming language
- A Kubernetes cluster (e.g., Minikube, kind, or any cloud-based Kubernetes service)
kubectlcommand-line tool installed
- The Go programming language (version 1.16+) installed
- The Operator SDK installed
Table of Contents
- What are Kubernetes Operators?
- Setting Up the Development Environment
- Creating a Custom Resource Definition (CRD)
- Implementing the Operator
- Deploying the Operator
- Testing the Operator
What are Kubernetes Operators?
Kubernetes operators are custom controllers that extend the Kubernetes API to manage complex applications. They allow you to define custom resources and provide the necessary automation to handle them.
Setting Up the Development Environment
First, create a new directory for your operator:
Initialize the project with the
This command creates your operator’s necessary files and directories, including the
Makefile, and the Go module.
Creating a Custom Resource Definition (CRD)
Now, create a custom resource definition (CRD) for your operator:
This command generates the following files:
api/v1alpha1/myapp_types.go: Defines the MyApp custom resource (CR)
controllers/myapp_controller.go: Implements the MyApp controller
Edit api/v1alpha1/myapp_types.go to define the MyApp CR spec and status:
After defining the CRD, run the following command to update the generated code:
Implementing the Operator
Next, open the
controllers/myapp_controller.go file to implement the
MyApp controller. Start by importing the necessary packages at the top of the file:
Reconcile method in the
Now, implement the logic to create and manage your application’s
Deployment and a
Service. You can find examples in the official Kubernetes client-go example repository.
Deploying the Operator
Build and push the operator image:
Deploy the operator to your cluster:
Testing the Operator
Create a sample
MyApp custom resource:
Save this as
myapp-sample.yaml, then apply it to your cluster:
Check if the operator creates the
Service for your application:
In this guide, you have learned how to create a Kubernetes operator using the Go programming language and the Kubernetes Operator SDK. You can now extend the Kubernetes API to manage complex applications and automate tasks on your cluster.
Subscribe to Faizan Bashir
Get the latest posts delivered right to your inbox