Book Image

Getting Started with Kubernetes - Third Edition

By : Jonathan Baier, Jesse White
Book Image

Getting Started with Kubernetes - Third Edition

By: Jonathan Baier, Jesse White

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. Based on the recent release of Kubernetes 1.12, Getting Started with Kubernetes gives you a complete understanding of how to install a Kubernetes cluster. The book focuses on core Kubernetes constructs, such as pods, services, replica sets, replication controllers, and labels. You will understand cluster-level networking in Kubernetes, and learn to set up external access to applications running in the cluster. As you make your way through the book, you'll understand how to manage deployments and perform updates with minimal downtime. In addition to this, you will explore operational aspects of Kubernetes , such as monitoring and logging, later moving on to advanced concepts such as container security and cluster federation. You'll get to grips with integrating your build pipeline and deployments within a Kubernetes cluster, and be able to understand and interact with open source projects. In the concluding chapters, you'll orchestrate updates behind the scenes, avoid downtime on your cluster, and deal with underlying cloud provider instability within your cluster. By the end of this book, you'll have a complete understanding of the Kubernetes platform and will start deploying applications on it.
Table of Contents (23 chapters)
Title Page
Dedication
Packt Upsell
Contributors
Preface
Index

Advanced services


Let's explore the IP strategy as it relates to services and communication between containers. If you recall, in the Services section of 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...