Book Image

Kubernetes for Developers

By : Joseph Heck
Book Image

Kubernetes for Developers

By: Joseph Heck

Overview of this book

Kubernetes is documented and typically approached from the perspective of someone running software that has already been built. Kubernetes may also be used to enhance the development process, enabling more consistent testing and analysis of code to help developers verify not only its correctness, but also its efficiency. This book introduces key Kubernetes concepts, coupled with examples of how to deploy and use them with a bit of Node.js and Python example code, so that you can quickly replicate and use that knowledge. You will begin by setting up Kubernetes to help you develop and package your code. We walk you through the setup and installation process before working with Kubernetes in the development environment. We then delve into concepts such as automating your build process, autonomic computing, debugging, and integration testing. This book covers all the concepts required for a developer to work with Kubernetes. By the end of this book, you will be in a position to use Kubernetes in development ecosystems.
Table of Contents (16 chapters)
Title Page
Packt Upsell
Contributors
Preface
Index

Kubernetes resource – Annotations


Where labels and selectors are used for grouping and selecting sets of Kubernetes resources, Annotations provide a means of adding resource-specific metadata that can be accessed by either Kubernetes or in the containers it runs.

As you just saw, kubectl apply automatically applies an annotation to track the last applied configuration state of a resource when it is invoked. In the last chapter, you might have noticed the annotation that the deployment controllers used to track revision, deployment.kubernetes.io/revision, and we spoke of the kubernetes.io/change-cause annotation that was used by kubectl to display the change history of deployment rollouts.

Annotations can be simple values or complex blocks (as in the case of kubectl.kubernetes.io/last-applied-configuration). The examples so far are Kubernetes tools using annotations to share information, although annotations are also used to share information in a container for an application to use.

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