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

Implementing leader election

Leader election is an important concept in any distributed computing system, not just Kubernetes (and not just for Operators, either). High-availability applications will often deploy multiple replicas of their workload Pods to support the uptime guarantees their users expect. In situations where only one workload Pod can do work in a cluster at a time, that replica is known as the leader. The remaining replicas will wait, running but not doing anything significant, until the current leader becomes unavailable or gives up its status as the leader. Those Pods will then determine among themselves who should be the new leader.

Enabling proper leader election can greatly benefit the application's uptime. This can include graceful failover handling if one replica fails, or help to maintain application accessibility during rolling upgrades.

The Operator SDK makes leader election for Operators simple to implement. The boilerplate code scaffolded by...