[kerny]

> The're VM's

They are definitely not VMs.

> But they're really, really efficient compared to VM's.

I think that the virtualisation CPU overhead is below 1%. Layered file systems are possible with virtual machines as well so disk space usage could be comparable.

What do you mean that they are "really, really efficient" ?

[RantyDave]

5-10%, realistically, with some very informal testing. Not really a particularly big deal.

Really really efficient relates to how many containers can be run on a given system vs VM's. About 10x as many.