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

Taints and Tolerations

Previously, we have seen how Pods can be configured to control which node they run on. Now we will see how nodes can control which Pods can run on them using taints and tolerations.

A taint prevents the scheduling of a pod unless that Pod has a matching toleration for the Pod. Think of taint as an attribute of a node and a toleration is an attribute of a Pod. The Pod will get scheduled on the node only if the Pod's toleration matches the node's taint. The taints on a node tell the scheduler to check which Pods tolerate the taint and run only those Pods that match their toleration with the node's taint.

A taint definition contains the key, value, and effect. The key and value will match the Pod toleration definition in the Pod specification, while the effect instructs the scheduler what should be done once the node's taint matches the Pod's toleration.

The following diagram provides an overview of how the process of controlling...