Is there an OS distribution to run virtual machines?

Question

Virtualization

A long time ago I saw a video on YouTube. 2 win 7 and ubuntu virtual machines were demonstrated there at once, between which it was possible to switch with some kind of keyboard shortcut. And when the dude pressed something, he got some kind of gui, where all his virtual machines were shown. Moreover, it all looked as if there was some kind of special linux distribution kit, in which there is nothing but the virtual machine software itself.

I saw it about 4 years ago, and I don’t remember any details. Please tell me if there is something similar? Or something similar?

upd: just in case, I'll clarify that I understand that almost any OS can be used. But I'm interested in a custom solution. Or instructions and someone's developments on how to make a special solution from some distribution

Answer 1

Maybe there was some kind of Proxmox or oVirt?

Answer 2

Of course there is: Ubuntu.

Answer 3

There is. It is called "almost any GNU / Linux distribution" (exceptions are highly specialized).

Answer 4

VMware vSphere Hypervisor?