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

StatefulSets

StatefulSets are a stable resource in the apps/v1 API group. Their use case is stateful components of your application, such as Pods that are not intended to be ephemeral and need more order than is provided by something such as a Deployment.

Stateful components of a microservices application are usually the hardest to implement, and platforms such as Kubernetes have been somewhat slow to implement features to handle them. StatefulSets are a step toward improving this.

In many ways, StatefulSets are like Deployments. For example, we define them in a YAML file that we POST to the API server as a desired state. A controller implements the work on the cluster and a background watch loop makes sure that the current state matches the desired state. However, there are several significant differences. These include:

  • StatefulSets give Pods deterministic and meaningful names. Deployments do not.
  • StatefulSets always start and delete Pods in a specific order. Deployments...