Certified Kubernetes Application Developer (CKAD) Study Guide, 2nd Edition

Chapter 2. Kubernetes in a Nutshell

It’s helpful to get a quick rundown of what Kubernetes is and how it works if you are new to the space. Many tutorials and 101 courses are available on the web, but I would like to summarize the most important background information and concepts in this chapter. In the course of this book, we’ll reference cluster node components, so feel free to come back to this information at any time.

What Is Kubernetes?

To understand what Kubernetes is, first let’s define microservices and containers.

Microservice architectures call for developing and executing pieces of the application stack as individual services, and those services have to communicate with one another. If you decide to operate those services in containers, you will need to manage a lot of them while at the same time thinking about cross-cutting concerns like scalability, security, persistence, and load balancing.

Tools like buildkit and Podman package software artifacts into a container image. Container runtime engines like Docker Engine and containerd use the image to run a container. This works great on developer machines for testing purposes or for ad-hoc executions, e.g., as part of a Continuous Integration pipeline. For more information on containers, refer to Chapter 4.

Kubernetes is a container orchestration tool that helps with operating hundreds or even thousands of containers on physical machines, virtual machines, or in the cloud. Kubernetes can also fulfill those cross-cutting ...