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

Summary

This chapter outlined the details of an Operator we would like to build. Beginning with a description of the problem (in this case, a simple Operator to manage an nginx Pod) gave a solid foundation of the solutions that are available to work with. This step even provided enough information to set a goal for the capability level of this Operator (Level II – Seamless Upgrades).

The next step was outlining what the Operator CRD will look like. To do this, we first noted some relevant conventions in the Kubernetes API that are helpful to ensure the Operator conforms to expected standards for Kubernetes objects. We then broke down the structure of a CRD and explained how each section relates to the corresponding CR object. Finally, we drafted an example of what the Operator's CR will look like in the cluster to get a concrete idea of the expectation from users.

After designing the CRD, we considered our options for managing additional resources as well. For an...