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 – ReplicaSet


A ReplicaSet wraps Pods, defining how many need to run in parallel. A ReplicaSet is commonly wrapped in turn by a deployment. ReplicaSets are not often used directly, but are critical to represent horizontal scaling—to represent the number of parallel Pods to run.

A ReplicaSet is associated with a Pod and indicates how many instances of that Pod should be running within the cluster. A ReplicaSet also implies that Kubernetes has a controller that watches the ongoing state and knows how many of your Pod to keep running. This is where Kubernetes is really starting to do work for you, if you specified three Pods in a ReplicaSet and one fails, Kubernetes will automatically schedule and run another Pod for you.