Book Image

The Kubernetes Workshop

By : Zachary Arnold, Sahil Dua, Wei Huang, Faisal Masood, Mélony Qin, Mohammed Abu Taleb
5 (1)
Book Image

The Kubernetes Workshop

5 (1)
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

Understanding StatefulSets

In Figure 14.1, we can see that a StatefulSet is invoked to be able to manage pod life cycles. A StatefulSet (in older versions of Kubernetes, this was called a PetSet) operates very similarly to a Deployment in that we provide a pod template of what we want to run and how many instances of it we want to run. What differs between a StatefulSet and a Deployment is the following:

  • A clear naming scheme that can be depended upon by pods in DNS queries:

    This means that in the preceding diagram when we name a StatefulSet mysql, the first pod in that StatefulSet will always be mysql-0. This is unlike a traditional deployment where pod IDs are assigned randomly. It also means that if you had a pod named mysql-2 and it crashed, it would be resurrected on the cluster using exactly the same name.

  • A clearly ordered way in which updates must proceed:

    Depending on the update strategy in this StatefulSet, each pod will be taken down in a very specific order. So...