There have been rumblings in recent months that VMware might be preparing to support Microsoft’s Hyper-V after string of commands was found buried in VMware’s vSphere 4.1 release that appeared able to detect whether Hyper-V or Xen “guest hypervisors” were present. VMware Labs also released a “fling” called XVP Manager capable of importing Hyper-V VMs into vCenter for basic management and for conversion into vSphere VMs.

With several management products on the market that sit above the hypervisor, Maritz was asked: Why not offer heterogeneous hypervisor management?

“There’s a significant technical cost to doing that,” Maritz said during a Q&A session following the vSphere 5 announcement. The real integration among disparate hypervisors doesn’t occur at the higher levels of management, Maritz said. Rather, “when you’re doing the sophisticated things – the Storage DRS, etcetera – that we’re talking about… those hypervisors down at the bottom [of the stack] are talking to each other constantly in realtime at very high speed and above all there’s extraordinarily high levels of reliability that you need. That stuff just has to work, period.”

In addition to technical hurdles to providing higher-level services for multiple hypervisors, VMware’s focus on ESXi is also a business decision, he said. “When you start putting other hypervisors in there, now you’ve increased your test matrix by a factor of three – those 2 million hours of testing now become 6 million hours, or 8 million hours of testing that you have to go through.”

And at the end of the day, “customers don’t want to spend their time testing this stuff,” Maritz said. “[virtual] infrastructure has become like a building – extraordinarily important – if you don’t have a building, you can’t operate — but it’s not going to differentiate you from your competitors.”