Having ran my home (and work) lab environments with many different virtualization systems, in the end, I always keep coming back to VMware. ESXi in particular. These days, with GPU pass-through, you can make it a workstation and a server at the same time. It's free for personal use and it's rock solid.
Any idea if one can emulate different versions of OpenGL too? I'm trying to figure out a sustainable way to test across versions without needing a lot of hardware.