One way to look at Kubernetes is to say that it consists of a database of arbitrary objects and controller programs that take actions when those objects change.

This is a good system to control software deployment (i.e. controllers react to objects that represent the desired state of a set of containers and a way to access them) but it can be a lot more generic than that.

Kubernetes isn't like other systems where the core is locked down and users can add plugins that have limited privileges but aren't really the same as the built-in stuff -- examples include browser extensions, or maybe Lua plugins for Nginx.

In Kubernetes you can create objects and controllers that are first-class citizens just like the ones it comes with out of the box. They go in the same database as the built-in objects. You can remove or replace parts of the core system if you want to. This is what makes it a platform.

Yep this is exactly the way I think about it. It’s a kernel for a distributed operating system.

Wait until you see how much RAM that needs. Take a look at a lightweight alternative like OpenFaaS, but yes: the Internet is your computer.