Build Your Own Kubernetes Operators with Go and Kubebuilder – Full Course

By freeCodeCamp.org
Published: Jan 15, 2026

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In this hands-on Kubernetes Operator course, you will learn how to extend Kubernetes by building your own custom operators and controllers from scratch. You’ll go beyond simply using Kubernetes and start treating it as a Software Development Kit (SDK).

You will learn how to build a real-world operator that manages AWS EC2 instances directly from Kubernetes, covering everything from the internal architecture of Informers and Caches to advanced concepts like Finalizers and Idempotency.

? Code & Resources: https://github.com/shkatara/kubernetes-ec2-operator

Shubham: https://www.linkedin.com/in/shubhamkatara/
Saiyam: https://www.linkedin.com/in/saiyampathak
Kubesimplify: https://www.youtube.com/@kubesimplify

Course Curriculum & Timestamps
Part 1: The Theory of Controllers
– 0:00:00 Introduction & Prerequisites
– 0:01:55 What is a Controller? (The Observe-Compare-Act Loop)
– 0:06:45 Idempotency in Controllers
– 0:07:55 Deep Dive: The Reconcile Loop (Happy Path, Sad Path, & Error Handling)
– 0:19:45 The Foundation of Writing Operators
– 0:23:05 What is an Operator? (The “Helper” Analogy)
– 0:27:35 CRDs (Custom Resource Definitions) and CRs (Custom Resources)
Part 2: Kubernetes Extensibility
– 0:31:35 Kubernetes as an SDK & Extensibility
– 0:34:00 Networking, Storage, & Admission Controllers
– 0:35:20 Internal Developer Platforms (IDP) & Platform Engineering
– 0:39:50 Bootstrapping with Kubebuilder
Part 3: Setting Up the Environment
– 0:41:05 Setting up the Local Environment (K3D, Docker)
– 0:52:15 Introduction to the Kubebuilder Framework
– 0:56:35 Project Initialization (kubebuilder init)
– 1:00:30 Exploring Scaffolding (Makefiles, Dockerfiles, main.go)
Part 4: Building the API & Logic
– 1:04:15 Creating your first API (kubebuilder create api)
– 1:06:45 Defining EC2 Instance Types & Specs in Go
– 1:13:05 Understanding TypeMeta and ObjectMeta
– 1:21:45 Internal Controller Logic Breakdown
– 1:24:05 Deep Dive: Manager Architecture & Controller-Runtime
– 1:31:05 Cert Watchers, Health Checks, & Prometheus Metrics
– 1:52:55 Initializing the Manager in main.go
Part 5: Hands-on Development
– 2:07:35 Implementing the Reconcile Loop Logic
– 2:22:35 Custom Resource Definitions (CRDs) in Action
– 2:46:45 Running the Operator Locally
– 3:01:45 AWS SDK Integration in Go
– 3:22:55 Using Finalizers for Cleanup Logic
– 3:36:55 Creating EC2 Instances on AWS via the Operator
– 3:53:20 Implementing Waiters for Instance State (Running/Terminated)
Part 6: Advanced Internals & Deployment
– 4:13:45 Idempotency & Reconciler Loop Internals
– 4:46:35 How Informers, Caches, and WorkQueues Work
– 5:11:20 Handling Object Deletion & Timestamps
– 5:32:05 Packaging the Operator with Helm
– 5:43:05 Deploying to Kubernetes (RBAC & Service Accounts)
– 6:16:20 Conclusion & Future Steps

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