###Get Ubuntu minimal in OpenVZ from here http://download.openvz.org/template/precreated/ Lots of VZ templates here (many more than you can install from Proxmox interface)
Follow this guide to configure the network (which won't work out of the box) https://openvz.org/Ubuntu_without_templates
Stop using vmbr and use veth instead! Then you can configure ubuntu/debian just like a baremetal server with a static IP https://help.ubuntu.com/lts/serverguide/network-configuration.html#ip-addressing
I think even CentOS should work fine on a fresh container with veth, as long as you use veth first and don't have a vmbr to clean up (i have done it, somehow, once, and I never want to go through that again)_
sudo apt-add-repository ppa:ubuntu-mate-dev/ppa
sudo apt-add-repository ppa:ubuntu-mate-dev/trusty-mate
sudo apt-get update
sudo apt-get upgrade
sudo apt-get install --no-install-recommends mate-desktop-environment