Is there a separate operating system in Pod?

A Kubernetes Pod does not contain a separate operating system. A Pod is an abstraction that groups one or more containers running on the same host and sharing network and storage resources. Containers within a Pod use the host operating system kernel on which Kubernetes is running and are isolated at the namespace and cgroups level, but do not have their own OS. Therefore, a Pod is more of a logical deployment unit rather than a full virtual machine with a separate OS.