Virtualization offers many potential savings through server consolidation and reduced server administration labor. But it also poses the age-old hazard of vendor lock-in. The field is young enough that the market leader, VMware, and the bigger companies that are following in its footsteps have not yet been called to account for their proprietary moves. But that's increasingly hard to bear when there's a solution so close at hand.

IT, against its better judgment, is moving toward managing a multihypervisor environment, much like the challenge it's confronted in multiple database systems, various PC architectures, and incompatible browsers. With Microsoft's Hyper-V part of Windows Server 2008, it's inevitable some corner of the enterprise will experiment with it, become dependent on it, and finally ask IT to support it.

One response is for every IT department to gain the expertise needed to manage the virtual machines of each hypervisor supplier. A wiser response would be for the hypervisor vendors to stop pursuing competitive distinctions through the small differences built into their respective virtual machines and start implementing the Open Virtual Machine Format (OVF).

OVF is a specification established by the Distributed Management Task Force, a respected standards body that can be entrusted with safeguarding its neutrality. It was backed as a draft proposal by Dell, HP, IBM, Microsoft, VMware. and XenSource when they submitted it to DMTF a year ago. I believe VMware originated it when it saw Citrix/XenSource agree to jointly make use of Microsoft's Virtual Hard Disk format. Microsoft and Citrix had the potential power to establish VHD as a de facto standard in certain corners of the marketplace, and rather than wait for such a thing to happen, VMware proposed a neutral format that many parties could back.

All the major hypervisor suppliers say they are willing to support Open Virtual Machine Format, and in one way or another they do. But they don't base their own proprietary products' operation on it. When it comes to managing the virtual machines of a competitor's hypervisor, both VMware and Citrix do so by converting them to their own format.

This persistence of competitive differentiation in virtual machines is the short-term maker of profits and the long-term maker of mischief, if I'm correct in assuming many enterprises will be multiple hypervisor environments.

Meanwhile, the task of managing the virtual machines produced by different hypervisors (without converting them to a single vendor's format) is being left to startups. Surgient manages both VMware and Microsoft Hyper-V virtual machines. Vizioncore, a unit of Quest Software, plans to add Hyper-V support to vFoglight, which currently manages virtual machines VMware's ESX Server.

DyanmicOps, the spin off from Credit Suisse, can manage VMware, XenServer, or Hyper-V-based virtual machines. It's perhaps telling that Credit Suisse built the ability to do so in-house after recognizing that an international financial services company was going to end up using multiple hypervisors.

Fortisphere relies on Open Virtual Machine Format as the basis for managing ESX, XenServer, and Hyper-V virtual machines.

Q-Layer, ManageIQ, and other startups are taking the lead in this demanding area.

And they are likely to be the best solution until users start persistently asking their virtualization vendor how the enterprise can implement Open Virtual Machine Format with their products. Even if you opt to rely on an independent third party with a multihypervisor approach, there's no reason its management tools wouldn't be strengthened by wider adoption of OVF.

As best I can tell, it is a good virtual machine design, with well-thought-out, built-in security features. So where are VMware, Microsoft and Citrix/XenSource making use of it? They sponsored OVF so they could all claim to be supporters of an open standard. OK, you support open standards. Next question: Where do you implement them?