As a refresher, let's remind ourselves about the entire Kubernetes system, so we can understand conceptually where the ecosystem referred to in this chapter sits:

In this chapter, we're talking about the top, greenest layer in the preceding diagram. This layer is made up of hundreds of companies and products that power the software and frameworks needed to run Kubernetes at scale. You can find the highest level of grouping of this layer in a couple of places:

• The first place to check is the Kubernetes Community GitHub repository:
  • You can find the repository at https://github.com/kubernetes/community, and it's a good starting point for anyone who's interested in joining the code-powered portions of the Kubernetes system. In the preceding diagram, consider the layers nucleus through interface, that is, layers one through four. Here's where we'll find the Special Interest Groups (SIGs), which will allow us to branch us out into the ecosystem layer where we can explore the supporting technologies that enable Kubernetes to stay focused on its core functionality.
• The second place you can investigate to dig deeper into the ecosystem is the CNCF landscape:
  • The landscape is actually broken up into a few useful parts that can help anyone from individual users, all the way up to large enterprises, make decisions on what technology to adopt, what to wait on, and what to leave behind. Here's where we'll really dig into the supporting ecosystem in order to understand what's meant to be in Kubernetes core, and what's meant to be provided by the ecosystem.

The Kubernetes documentation neatly answers the question, what is Kubernetes with the following quote:

So, if that's what Kubernetes is, what isn't it?