Proxmox been great for decades. I used it back in 2011 when I was sysadmin for https://sahanafoundation.org/eden/ - we had multiple live instance running for the site, wiki, translation, GIS. Just when kvm was getting support too (not openvz) so it was nice an snappy running on some donated poweredge 2950's (thanks zen.co.uk!)

Deployed for Haiti, Chengdu etc. All ran perfectly.