Chapter 11. Understanding Kubernetes internals
This chapter covers
- What components make up a Kubernetes cluster
- What each component does and how it does it
- How creating a Deployment object results in a running pod
- What a running pod is
- How the network between pods works
- How Kubernetes Services work
- How high-availability is achieved
By reading this book up to this point, you’ve become familiar with what Kubernetes has to offer and what it does. But so far, I’ve intentionally not spent much time explaining exactly how it does all this because, in my opinion, it makes no sense to go into details of how a system works until you have a good understanding of what the system does. That’s why we haven’t talked about exactly how a pod is scheduled or how the various controllers running inside the Controller Manager make deployed resources come to life. Because you now know most resources that can be deployed in Kubernetes, it’s time to dive into how they’re implemented.
Before you look at how Kubernetes does what it does, let’s take a closer look at the components that make up a Kubernetes cluster. In chapter 1, you saw that a Kubernetes cluster is split into two parts:
- The Kubernetes Control Plane
- The (worker) nodes
Let’s look more closely at what these two parts do and what’s running inside them.