>Docker can run on lxc or in kernel namespaces.
This is kind of an odd statement. All lxc is is userspace tools for managing namespaces and cgroups. If you're using lxc, you're still running on kernel namespaces
True, I should have said it can use lxc (which they used to use by default) or their own libcontainer to manage kernel namespaces. And I'm not sure what they're using to manage containers on Windows.
I'm just now diving into docker. Docker is really about the images. Docker can run on lxc or in kernel namespaces. And there is ongoing work to port Docker to FreeBSD where Docker images will run in jails.
But apparently it took Docker image format and registry to make it popular enough among developers to make contanerization the old new big thing.