The article starts on waffling about LXD then morphs into talking Unbutu Openstack with no clear segue. Now I guess the LXD stuff is only supported via an open stack deployment - or is it baked in more generally?
Canonical has kicked out its container management architecture for the suits with Ubuntu 15.10. The Linux spinner is today expected to drop its latest disro with the server including final code for its Linux Container Hypervisor (LXD). LXD is Canonical’s container management environment which it claims is similar to a …
It's like controlled fusion: always one release into the future (sadly).
It should be available as option, but it's supposed to be default in 16.10 in one year. Although I don't blame them for not sticking a completely new and untested software in a Long Term Support release like 16.04 will be.
Mir is for mobile, which is where you can find it now. It will eventually replace X on desktop Ubuntu, but not yet.
XMir is to let software which uses X directly emulate X under Mir. There's not a lot of that, since most go through GTK or Qt, which will have Mir support compiled in directly.
The reason for the Mir versus Wayland versus X is that Canonical wants to focus on producing something that works well on mobile but can be extended to the desktop, while the Wayland backers are mainly interested in something that works well on the desktop but may be extended to mobile. In other words they are starting on the problem space from opposite ends with different priorities. Android uses something called Surfaceflinger, but I don't think it can do complex multi-window, multi-desktop stuff for use on desktops and Google doesn't seem interested in following it up.
Wayland is backed mainly by Red Hat and Intel, the first of which tends to think that time spans of a decade constitutes "rapid innovation", while the second isn't interested in anything that doesn't sell more Intel chips. Canonical thinks there is only a narrow window of opportunity for GNU/Linux (as opposed to Android/Linux) to get on mobile, and aren't content to wait for anyone else so they took their own ball and are running with it.