On: My VM is lighter (and safer) than your container (...

[kevincox]

The isolation I am referencing is from the VM, not the container. Containers don't provide strong isolation, that is why the VM is required in this model.

[nailer → kevincox]

The VM is an isolated environment itself. You do not need to be isolated from it.

Using two levels of userland isolation makes about the same sense as using 457 levels of userland isolation.