I asked, how's progress coming on a neutral VM runtime format that could be recognized by all the hypervisor vendors? Winston Bumpus, president of the DMTF, said: "Nothing is under way at the moment. Nobody's proposed that we undertake that work."Maybe it's just me, but as Windows Server 2008 came out with the Hyper-V hypervisor built in, I could foresee it getting installed in departments, lines of business, and sub-data centers in branch offices, where experimenters would start working with this latest and greatest cheap Windows technology.

Right now, that presents a management nightmare, with virtualization tools largely designed to see one VM or the other, but not all of them.

It's happened before. Linux first crept in the back door when the IT manager wasn't looking. Microsoft's SharePoint got established before IT realized it was spreading like kudzu out there beyond the glass walls. What's going to stop Hyper-V virtual machines from taking off beneath the central IT radar as a cheap alternative to going through the agonizing process of getting another server out of the purchasing department? IT doesn't approve? Hasn't stopped 'em before.

And once Hyper-V gets a toehold, it will spread until one day the IT manager realizes he's got to manage the Hyper-V virtual machines alongside his VMware or Citrix XenServer virtual machines. Maybe he's got to manage all three, and throw in a stray Virtual Iron, Sun xVM, or Oracle VM virtual machine -- all members of the open source Xen family of hypervisors, but each one different -- as well. Wouldn't it be nice if users had the option of regenerating them all to run in a neutral format that could be recognized by any hypervisor?

Well, that prospect troubles the thinking of the big virtualization suppliers very little.

Winston Bumpus, president of the DMTF (formerly known as the Distributed Management Task Force), said his standards body is focused on Open Virtual Format or OVF, a common deployment virtual file format. He says the vendors have agreed only on a common deployment format, not a runtime format. That may be as close to a neutral standard as we're going to get.

That means a sleeping virtual machine can be pulled out of storage, given a wrapper that explains in what sequence its essential characteristics and functions appear, and then moved under a hypervisor that decodes the information to convert the virtual machine into its own preferred format. ESX Server from VMware can spot and convert a virtual machine originally generated by Citrix XenServer in the VHD format. Likewise, XenServer can see and convert a virtual machine originally generated by ESX Server in the VMDK format.

Since the XenSource unit of Citrix and Microsoft have agreed to use the same runtime VHD format, I think it's possible to say these capabilities will extend to virtual machines generated by Hyper-V.

This approach sort of gets us to where we want to go. But if Microsoft and XenSource can agree on a shared runtime format, why can't everybody? Why not settle on a neutral runtime format that eliminates the need to convert the alien into a citizen of a particular hypervisor's realm. The vendors could keep their proprietary VMs, but there would be an alternative, the option for a VM to be a citizen of the world with a passport to move around, regardless of governing hypervisor.

It's academic today. Few IT managers -- probably none of them in their right minds -- are striving to create a mixed hypervisor environment with all the management headaches that would accompany such a move.

I'm saying that mixed environment is going to eventually arise anyway, regardless of whether the IT manager approves. See Virtualization Vendors, Time To Walk The Walk, Not Just Talk.

Someday we'll spend a lot of time standing around saying, "Wouldn't it be nice, back at creation, if everybody had agreed to a shared runtime environment." If we once thought OVF would be it, let's get over that.

Bumpus is only being realistic when he says the vendors aren't lobbying for such a thing, and neither the DMTF or any other standards body is going to impose it on them without their consent. But customers, getting deeper into virtualization by the day, should sit their virtualization salesman down for a heart-to-heart chat about the future and how wise it would be to get a neutral standard available in this area.