It’s really simple and lot of people already know that : GOOGLE !!
Since 2004, Google uses an operating system named Borg. This tool solves problem like :
how to manage large number of servers ?
how to deploy/manage apps on this kind of infrastructure ?
how to move easily an app or many apps to accept a maintenance window on a server ?
etc
And after 10 years, Google decided to keep Borg concepts and developed a new tool. In 2014, Google provided Kubernetes in its first opensourced version. Google gave this k8s to the Cloud Native Computer Foundation (CNCF).