I have been running several different virtualisation servers, (ESXi, XenServer, Proxmox/KVM) in the past. I am now in a position where I need to set up a new virtualisation environment that is supposed to be long running. I figured it might be a good idea to be prepared for Docker as it comes up quite often lately. I have used vagrant in development environments very successfully, but not yet docker containers but will possibly start soon.
My question is, which would be the best virtualization platform to allow me to include docker at a later point? I would love to stay with something built around Xen (preferably not the Citrix flavor) but anything else would be ok as well. Guest machines will most likely only be Linux with perhaps an occasional *BSD. I cannot set up two systems, so the docker containers will have to live on the same hardware as the virtual machines. (For the single machine reason I would also like to avoid OpenStack, unless it would be the ideal match for docker + VMs).
Any advice what virtualization infrastructure is going to play nice with docker?