[$] Containers as a recognized kernel object

The foundation of the design for containers in the kernel is that thereisn't one; there is no container abstraction that the kernel recognizes.Instead, the kernel provides a long list of components - namespaces,control groups, sandboxing mechanisms, and more - along with a note thatsays, in effect, "some assembly required". There have been attempts (repeatedly) over the years to turn containersinto first-class objects with kernel support, but they have never gottenfar. Now Josef Bacik is making atry with a concept that he calls "cells".