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

Kubernetes HTTP Request Flow

As we learned in earlier chapters, when we run any kubectl command, the command is translated into an HTTP API request in JSON format and is sent to the API server. Then, the API server returns a response to the client, along with any requested information. The following diagram shows the API request life cycle and what happens inside the API server when it receives a request:

Figure 4.2: API server HTTP request flow

As you can see in the preceding figure, the HTTP request goes through the authentication, authorization, and admission control stages. We will take a look at each of these in the following subtopics.

Authentication

In Kubernetes, every API call needs to authenticate with the API server, regardless of whether it comes from outside the cluster, such as those made by kubectl, or a process inside the cluster, such as those made by kubelet.

When an HTTP request is sent to the API server, the API server needs to...