What is Kubernates?

Reason

Reason I posted this is while I was trying to build home-server, I got confused within using docker or not.
When I searched about docker, most people talked about kubernetes.
This is reason why I post about Kubernetes. And if it contains wrong info, please leave comments.

What is Kubernetes?

Previous when it doesn’t have Kubernetes, programmers usually put apps on an Operating System.
Then when it comes to Virtualized Deployment, they put app in the virtual machine which is on the Hypervisor.
After using Kubernetes, Hypervisor become Container Runtime and Virtual Machine become Container which only contains app and bin/library.