Please just post the link to the docs if you have to, do not spam our forum with walls of text or endless one liner threads with just some quote.
I was just trying to be helpful
So I spent much of last night listening to lectures on cgroups and namespace, and what I learned is that this is complex, with a poor interface, and difficult to learn, or even make much sense of. And yet the entire kernel is wrapped in cgroups . Obviously docker is at the front of promoting it and the complexty makes use use of helpful tools like Ansible, almost essential.