Book Image

The Kubernetes Operator Framework Book

By : Michael Dame
1 (1)
Book Image

The Kubernetes Operator Framework Book

1 (1)
By: Michael Dame

Overview of this book

From incomplete collections of knowledge and varying design approaches to technical knowledge barriers, Kubernetes users face various challenges when developing their own operators. Knowing how to write, deploy, and pack operators makes cluster management automation much easier – and that's what this book is here to teach you. Beginning with operators and Operator Framework fundamentals, the book delves into how the different components of Operator Framework (such as the Operator SDK, Operator Lifecycle Manager, and OperatorHub.io) are used to build operators. You’ll learn how to write a basic operator, interact with a Kubernetes cluster in code, and distribute that operator to users. As you advance, you’ll be able to develop a sample operator in the Go programming language using Operator SDK tools before running it locally with Operator Lifecycle Manager, and also learn how to package an operator bundle for distribution. The book covers best practices as well as sample applications and case studies based on real-world operators to help you implement the concepts you’ve learned. By the end of this Kubernetes book, you’ll be able to build and add application-specific operational logic to a Kubernetes cluster, making it easier to automate complex applications and augment the platform.
Table of Contents (16 chapters)
1
Part 1: Essentials of Operators and the Operator Framework
4
Part 2: Designing and Developing an Operator
9
Part 3: Deploying and Distributing Operators for Public Use

Upgrading Kubernetes

In software, upgrades are usually a fact of life. Very rarely is a single piece of software that lives for more than a brief time able to run continuously without upgrading its code to a new version. In Chapter 8, Preparing for Ongoing Maintenance of Your Operator, we discussed ways to prepare and publish new version releases of an Operator. In that chapter, we also explained the different phases of the Kubernetes release cycle and how they impact Operator development. This is especially true for Operators that are deeply entrenched in the Kubernetes platform components.

For system Operators, fluctuating changes in the upstream Kubernetes code base are often more than just simple features. For example, when kube-scheduler was refactored to accept an entirely different format of configuration (referred to as the Scheduler Framework, which is no relation to the Operator Framework – see https://kubernetes.io/docs/concepts/scheduling-eviction/scheduling-framework...