Book Image

Getting Started with Kubernetes, Second Edition - Second Edition

By : Jonathan Baier
Book Image

Getting Started with Kubernetes, Second Edition - Second Edition

By: Jonathan Baier

Overview of this book

Kubernetes has continued to grow and achieve broad adoption across various industries, helping you to orchestrate and automate container deployments on a massive scale. This book will give you a complete understanding of Kubernetes and how to get a cluster up and running. You will develop an understanding of the installation and configuration process. The book will then focus on the core Kubernetes constructs such as pods, services, replica sets, replication controllers, and labels. You will also understand how cluster level networking is done in Kubernetes. The book will also show you how to manage deployments and perform updates with minimal downtime. Additionally, you will learn about operational aspects of Kubernetes such as monitoring and logging. Advanced concepts such as container security and cluster federation will also be covered. Finally, you will learn about the wider Kubernetes ecosystem with OCP, CoreOS, and Tectonic and explore the third-party extensions and tools that can be used with Kubernetes. By the end of the book, you will have a complete understanding of the Kubernetes platform and will start deploying applications on it.
Table of Contents (20 chapters)
Title Page
Credits
About the Author
Acknowledgement
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Advanced services


Let's explore the IP strategy as it relates to services and communication between containers. If you recall, in the Services section, Chapter 2, Pods, Services, Replication Controllers, and Labels, you learned that Kubernetes is using kube-proxy to determine the proper pod IP address and port serving each request. Behind the scenes, kube-proxy is actually using virtual IPs and iptables to make all this magic work.

Kube-proxy now has two modes—userspace and iptables. As of now, 1.2 iptables is the default mode. In both modes, kube-proxy is running on every host. Its first duty is to monitor the API from the Kubernetes master. Any updates to services will trigger an update to iptables from kube-proxy. For example, when a new service is created, a virtual IP address is chosen and a rule in iptables is set, which will direct its traffic to kube-proxy via a random port. Thus, we now have a way to capture service-destined traffic on this node. Since kube-proxy is running on all...