If you’re looking to develop native applications in Kubernetes, this is your guide. Developers and AppOps administrators will learn how to build Kubernetes-native applications that interact directly with the API server to query or update the state of resources. AWS developer advocate Michael Hausenblas and Red Hat principal software engineer Stefan Schimanski explain the characteristics of these apps and show you how to program Kubernetes to build them.

You’ll explore the basic building blocks of Kubernetes, including the client-go API library and custom resources. All you need to get started is a rudimentary understanding of development and system administration tools and practices, such as package management, the Go programming language, and Git.

• Walk through Kubernetes API basics and dive into the server’s inner structure
• Explore Kubernetes’s programming interface in Go, including Kubernetes API objects
• Learn about custom resources―the central extension tools used in the Kubernetes ecosystem
• Use tags to control Kubernetes code generators for custom resources
• Write custom controllers and operators and make them production ready
• Extend the Kubernetes API surface by implementing a custom API server

Table of Contents

Chapter 1. Introduct ion

Chapter 2. Kubernetes API Basics

Chapter 3. Basics of client -go

Chapter 4. Using Custom Resources

Chapter 5. Automating Code Generation

Chapter 6. Solutions for Writing Operators

Chapter 7. Shipping Controllers and Operators

Chapter 8. Custom API Servers

Chapter 9. Advanced Custom Resources

Who Should Read This Book

You’re a developer going cloud-native, or an AppOps, or namespace admin wanting to get the maximum out of Kubernetes. Vanilla settings don’t do it for you anymore, and you may have learned about extension points. Good. You’re in the right place.

What is Programming Kubernetes?

Programming Kubernetes can mean different things to different people... We assume you have access to a running Kubernetes cluster such as Amazon EKS, Microsoft AKS, Google GKE, or one of the OpenShift offerings.

We also assume that you are a Go programmer—that is, you have experience or at least basic familiarity with the Go language.

By “programming Kubernetes” in the context of this book, we mean the following: you are about to develop a Kubernetes-native application that directly interacts with the API server, querying the state of resources and/or updating their state.

We do not mean running off-the-shelf apps, such as WordPress or Rocket Chat or your favorite enterprise CRM system, oftentimes called commercially available off-the-shelf (COTS) apps.

So, in a nutshell, this book is about developing genuinely cloud-native applications.

Why We Wrote This Book

Both of us have been contributing to, writing about, teaching, and using Kubernetes since early 2015.

We have developed tooling and apps for Kubernetes and given workshops about developing on and with Kubernetes a couple of times. At some point we said, “Why don’t we write a book?” This would allow even more people, asynchronously and at their own pace, to learn how to program Kubernetes. And here we are. We hope you have as much fun reading the book as we did writing it.

About the Author

Michael Hausenblas is an AWS developer advocate. Stefan Schimanski is a Senior Software Engineer at Red Hat.

Stefan Schimanski is a Senior Software Engineer at Red Hat.