Hi Mark ,
ALM Server can be installed on VMs.
Below is the extract from the ALM 11.5x system requirements page :
Virtual Environments VMWare ESX/ESXi Server 5.0 and higher.
HP ALM/QC is certified to work with VMWare ESX/ESXi. Due to the rapidly evolving architectures provided by Virtualization vendors as long as the above stated vendor guarantees full compatibility of the virtualized environment to the HP ALM/QC approved system requirements for physical hardware, then HP ALM/QC will function as designed.
Here is the link for the complete system requirement :
https://hpln.hp.com/page/alm-qc-enterprise-technical-specifications
As long the vendor supports out minimum hardware and software requirements , virtualization is supported.
ALM client machines can also be VMs. The link has details regarding it.
Regards,