Book Image

The Kubernetes Workshop

By : Zachary Arnold, Sahil Dua, Wei Huang, Faisal Masood, Mélony Qin, Mohammed Abu Taleb
Book Image

The Kubernetes Workshop

By: Zachary Arnold, Sahil Dua, Wei Huang, Faisal Masood, Mélony Qin, Mohammed Abu Taleb

Overview of this book

Thanks to its extensive support for managing hundreds of containers that run cloud-native applications, Kubernetes is the most popular open source container orchestration platform that makes cluster management easy. This workshop adopts a practical approach to get you acquainted with the Kubernetes environment and its applications. Starting with an introduction to the fundamentals of Kubernetes, you’ll install and set up your Kubernetes environment. You’ll understand how to write YAML files and deploy your first simple web application container using Pod. You’ll then assign human-friendly names to Pods, explore various Kubernetes entities and functions, and discover when to use them. As you work through the chapters, this Kubernetes book will show you how you can make full-scale use of Kubernetes by applying a variety of techniques for designing components and deploying clusters. You’ll also get to grips with security policies for limiting access to certain functions inside the cluster. Toward the end of the book, you’ll get a rundown of Kubernetes advanced features for building your own controller and upgrading to a Kubernetes cluster without downtime. By the end of this workshop, you’ll be able to manage containers and run cloud-based applications efficiently using Kubernetes.
Table of Contents (20 chapters)
Preface

ReplicaSets

As discussed earlier, having multiple replicas of our application ensures that it is still available even if a few replicas fail. This also makes it easy for us to scale our application to balance the load to serve more traffic. For example, if we are building a web application that's exposed to users, we'd want to have at least two replicas of the application in case one of them fails or dies unexpectedly. We would also want the failed replica to recover on its own. In addition to that, if our traffic starts growing, we would want to increase the number of Pods (replicas) running our application. A ReplicaSet is a Kubernetes controller that keeps a certain number of Pods running at any given time.

ReplicaSet acts as a supervisor for multiple Pods across the different nodes in a Kubernetes cluster. A ReplicaSet will terminate or start new Pods to match the configuration specified in the ReplicaSet template. For this reason, it is a good idea to use them even...