Book Image

Kubernetes and Docker - An Enterprise Guide

By : Scott Surovich, Marc Boorshtein
Book Image

Kubernetes and Docker - An Enterprise Guide

By: Scott Surovich, Marc Boorshtein

Overview of this book

Containerization has changed the DevOps game completely, with Docker and Kubernetes playing important roles in altering the flow of app creation and deployment. This book will help you acquire the knowledge and tools required to integrate Kubernetes clusters in an enterprise environment. The book begins by introducing you to Docker and Kubernetes fundamentals, including a review of basic Kubernetes objects. You’ll then get to grips with containerization and understand its core functionalities, including how to create ephemeral multinode clusters using kind. As you make progress, you’ll learn about cluster architecture, Kubernetes cluster deployment, and cluster management, and get started with application deployment. Moving on, you’ll find out how to integrate your container to a cloud platform and integrate tools including MetalLB, externalDNS, OpenID connect (OIDC), pod security policies (PSPs), Open Policy Agent (OPA), Falco, and Velero. Finally, you will discover how to deploy an entire platform to the cloud using continuous integration and continuous delivery (CI/CD). By the end of this Kubernetes book, you will have learned how to create development clusters for testing applications and Kubernetes components, and be able to secure and audit a cluster by implementing various open-source solutions including OpenUnison, OPA, Falco, Kibana, and Velero.
Table of Contents (20 chapters)
1
Section 1: Docker and Container Fundamentals
5
Section 2: Creating Kubernetes Development Clusters, Understanding objects, and Exposing Services
9
Section 3: Running Kubernetes in the Enterprise

Introduction to dynamic admission controllers

There are two ways to extend Kubernetes:

  • Build a custom resource definition so that you can define your own objects and APIs.
  • Implement a webhook that listens for requests from the API server and responds with the necessary information. You may recall that in Chapter 7, Integrating Authentication into Your Cluster, we explained that a custom webhook was used to validate tokens.

Starting in Kubernetes 1.9, a webhook can be defined as a dynamic admission controller, and in 1.16, the dynamic admission controller API became Generally Available (GA).

The protocol is very straightforward. Once a dynamic admission controller is registered for a specific object type, the webhook is called with an HTTP post every time an object of that type is created or edited. The webhook is then expected to return JSON that represents whether it is allowed or not.

Important note

As of 1.16, admission.k8s.io/v1 is at GA. All examples...