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

Probes 


The two probes enabled in Kubernetes are the liveness probe and readiness Probe. They are complimentary, but different in intent and usage, and can be defined for each container within a Pod. In both cases, they provide a means for your code to influence how Kubernetes manages the containers.

Liveness probe

The most basic probe is the Liveness probe. If defined, it provides a command or URL that Kubernetes can use to determine whether a Pod is still operational. If the call succeeds, Kubernetes will assume the container is healthy; if it fails to respond, then the Pod can be handled as the restartPolicy is defined. The result is binary: either the probe succeeds, and Kubernetes believes your Pod is running, or it fails, so Kubernetes believes your Pod is no longer functional. In the latter case, it will check with the defined RestartPolicy to choose what to do.

The default value for restartPolicy is Always, meaning if a container within the Pod fails, Kubernetes will always attempt...