Book Image

The Kubernetes Book

By : Nigel Poulton, Pushkar Joglekar
Book Image

The Kubernetes Book

By: Nigel Poulton, Pushkar Joglekar

Overview of this book

Kubernetes is the leading orchestrator of cloud-native apps. With knowledge of how to work with Kubernetes, you can easily deploy and manage applications on the cloud or in your on-premises data center. The book begins by introducing you to Kubernetes and showing you how to install it. You’ll learn how to use Kubernetes Services and bring stable and reliable networking to apps that are deployed on Kubernetes. You'll delve deep into the powerful storage subsystem of Kubernetes and learn how to leverage the variety of external storage backends in your applications. As the book progresses, it shows you how to use features such as DaemonSets, Helm, and RBAC to enhance your Kubernetes applications. You'll explore the six categories of identifying vulnerabilities and look at a few ways to prevent and mitigate them. You'll also look at ways to secure the software delivery pipeline by discussing some image-related best practices. The book ends by sharing with you some resources that’ll help take your Kubernetes knowledge to the next level. By the end of the book, you’ll have the confidence and skills to leverage all the features of Kubernetes to develop scalable applications.
Table of Contents (23 chapters)
Free Chapter
1
Chapter 1
3
Chapter 2
5
Chapter 3
7
Chapter 4
9
Chapter 5
11
Chapter 6
13
Chapter 7
15
Chapter 8
17
Chapter 9
19
Chapter 10
21
Chapter 11

Setting the Scene

Before diving in, we need to remind ourselves that Pod IPs are unreliable. When Pods fail, they get replaced with new Pods that have new IPs. Scaling up a Deployment introduces new Pods with new IP addresses. Scaling down a Deployment removes Pods. All of this creates a large amount of IP churn, and creates a situation where Pod IPs cannot be relied on.

We also need to know three fundamental things about Kubernetes Services.

First, we need to clear up some terminology. When talking about a Service in this chapter, we're talking about the Service REST object in the Kubernetes API. Just like a Pod, ReplicaSet, or Deployment, a Kubernetes Service is an object in the API that we define in a manifest and POST to the API server.

Second, we need to know that every Service gets its own stable IP address, its own stable DNS name, and its own stable port.

Third, we need to know that Services use labels to dynamically select the Pods in the cluster they will...