I managed to mess up posting this link yesterday, in spectacular fashion. Sorry for the fumbled PSA!
Nonetheless, if you want the world's fastest OpenStack, this is the webinar to watch today. It's about replacing all the machine virtualization in OpenStack with pure containers, which means for Linux workloads you get amazing density, performance, i/o and latency improvements.
LXD will sit nicely alongside KVM so you can of course have the best of both worlds - VMs for stuff that needs a non-Linux guest, and CMs ("container machines") for stuff on Linux you want to go really really fast and dense.