[ubuntu] Clustering without virtualization

Hi! I have lot of IBM servers and I want to make cluster. But Ibm´s motherboard didn´t support virtualization, only hyper threading. I checked few way to do cluster for example proxmox and beowulf.
Proxmox require virtualization , but if I understand right beowulf didtn´t need that? How it can be possible btw? :D

So, I´m wondering what is easiest to cluster all my servers? Can I cluster them with vmware or virtualbox,, Help me :D and thanx a lot :)