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

How to Perform a Rollback

A moment ago, we used kubectl apply to perform a rolling update on a Deployment. We used the --record flag so that Kubernetes would maintain a documented revision history of the Deployment. The following kubectl rollout history command shows the Deployment with two revisions.

$ kubectl rollout history deployment hello-deploy
deployment.apps/hello-deploy
REVISION  CHANGE-CAUSE
1         <none>
2         kubectl apply --filename-deploy.yml --record=true

Revision 1 was the initial deployment that used the latest image tag. Revision 2 is the rolling update we just performed, and we can see that the command we used to invoke the update has been recorded in the object's history. This is only there because we used the --record flag as part of the command to invoke the update. This might be a good reason for you to use the --record flag.

Earlier in the chapter, we said that updating a Deployment creates a new ReplicaSet, and that any previous ReplicaSets...