Operators: Where to Start (Shortcut) — 5-Hour Plan

You don’t know where to start?
Do you want to design an Operator to package your solutions?

I recommend the following plan — in just one day you can cover the foundations, and in about 5 hours you’ll have a strong base over the fundamentals to begin developing your own Operators.

(15 min) Start with the Quick Start
Ensure that you have Kubebuilder installed and run the initial commands:
👉 https://book.kubebuilder.io/quick-start

Quick Start — Prerequisites

• Kubebuilder: https://book.kubebuilder.io/quick-start
• KIND: https://book.kubebuilder.io/reference/kind
• kubectl: https://kubernetes.io/docs/tasks/tools/#kubectl
• Golang: https://go.dev/

(1 hour) Start with the basics
Kubebuilder’s Getting Started guide walks you through building your first Operator step by step:
👉 https://book.kubebuilder.io/getting-started

(15 min) Learn the core concepts
The CronJob tutorial explains Groups, Versions, and Kinds (GVKs) — essential to understanding how Kubernetes APIs are structured:
👉 https://book.kubebuilder.io/cronjob-tutorial/gvks

(30 min) Understand Watching Resources
Read how to watch and reconcile external resources efficiently, a key skill for building effective Operators:
👉 https://book.kubebuilder.io/reference/watching-resources

(15 min) Understand Finalizers
Learn how to use finalizers to manage cleanup logic when resources are deleted, ensuring Operators handle lifecycle events correctly:
👉 https://book.kubebuilder.io/reference/using-finalizers

(15 min) Understand Webhooks
Learn what webhooks are, how they’re used for validation, defaulting, and mutation, and why they are important for Operator design:
👉 https://book.kubebuilder.io/reference/webhook-overview

(1 hour min) Get hands-on with scaffolding
Use the deploy-image plugin to scaffold a project and explore the generated API, controller, and tests:
👉 https://book.kubebuilder.io/plugins/available/deploy-image-plugin-v1-alpha

kubebuilder init 

kubebuilder create api \
  --group example.com \
  --version v1alpha1 \
  --kind Busybox \
  --image=busybox:1.36.1 \
  --plugins="deploy-image/v1-alpha"

Ensure that you check:

• API scaffold under api/ (also see the markers, https://book.kubebuilder.io/reference/markers)
• Controller under internal/controller/ (read the reconciliation and see all concepts above applied)
• Controller tests and suite tests using ENVTEST(https://book.kubebuilder.io/reference/envtest)
• E2E tests under test/e2e/, which are called using GitHub Actions
• Push to GitHub: create a repo, push your project, and see everything running
• Explore the config/ directory where you have the manifests

For more on the project layout:
👉 https://book.kubebuilder.io/cronjob-tutorial/basic-project

(15 min) Learn Good Practices
Review the recommended practices for structuring, documenting, and maintaining your projects:
👉 https://book.kubebuilder.io/reference/good-practices