Considering that OS-level virtualization ecosystem in Linux has reached a certain level of maturity and that LXC/LXD are the best representatives of it in the userspace, it might be useful to keep track of other cloud orchestration/management solutions, or more humble IAAS platforms, that take advantage of OS-level virtualization via LXD.
Auth-N, role management, orchestration, resource accounting, and other operations, are important pieces of the puzzle.
Up to now I am aware of the following:
What about Cloudstack, anyone knows what is going on there? Are you aware of anything else?