Microsoft And Xen Team For Virtualization

Virtualization makes for odd bedfellows.

Microsoft announced today it will team up with open source virtualization supplier XenSource to run Linux virtual machines under its Windows Longhorn Server.

The move is a big extension of Microsoft's previous commitment to allow Linux virtual machines to run under Windows. In April, it said it would support Linux under its base virtualization product, Virtual Server. Now it's going to support the generation and management of many Linux virtual machines on its most advanced software.

Four years ago, Microsoft denounced open source code as an affront to intellectual property and explained why customers shouldn't want to run Linux in the first place. Now the company's bent on making it easier to do so. Microsoft clearly understands the wave of virtualization sweeping its customers' data centers. Many of those data centers are running Linux as well as Windows. Microsoft's Jeff Price, senior director for Windows Server, says: "Customers will definitely have multiple systems. They're asking, 'What are you doing to make our lives easier?' " Microsoft's answer is that it will add a virtualization hyper-visor, a more efficient invocation of virtualization, to Windows Longhorn server and it will support Linux virtual machines running under it. Longhorn server is due by the end of 2007 and the hyper-visor is due six months after Longhorn is released, Price said in an interview.

If Microsoft once had harsh words for open source code such as Xen, which generates Linux virtual machines, XenSource is willing to let bygones be bygones. XenSource was the commercial company founded by Xen's originators at the University of Cambridge, England, to support Xen."At XenSource, we're pretty excited about doing this work with Microsoft," says Frank Artale, VP of XenSource business development. He also says it is a "fantastic commercial opportunity for us."

XenSource plans to augment open source Xen with commercial products that leverage what the open source code can do. Instead of being limited to Linux, XenSource will offer its wares across both Linux and Windows environments, expanding its potential market at a stroke. Artale declined to say exactly what commercial products XenSource had in mind but said it will offer "a roadmap later this summer."

XenSource has made it clear in the past it will not enter the virtual machine deployment and management system market. But that still leaves plenty of room for XenSource to launch its own commercial offerings, Artale said.

Price said Microsoft will build support for Xen into future virtualization management tools that it already has in the works as part of its hyper-visor. A hyper-visor is an efficient form of virtualization that communicates directly with a processor, without exchanging calls with an intervening operating system. Microsoft's existing Virtual Server sits on top of the Windows operating system and generates a virtual machine by using existing Windows procedures and calls.

Bypassing the operating system means the virtualization software has a smaller footprint. So, with the hyper-visor approach virtualization would require fewer hardware resources--memory and storage, that is--and that can be a huge savings. But also, if a server goes down, it will no longer necessarily take all the virtual machines down with it, as happens when virtual software is tied into the operating system. This can simplify administrators' jobs.VMware, IDC's designated market leader in virtualization, offers an ESX Server hyper-visor and gives away its VMware Server, which uses the atop-the-operating system approach.

"Microsoft's commitment to customers is to build bridges across the industry with solutions that are interoperable by design," said Bob Muglia, Microsoft's senior vice president of Server and Tools Business in the press release announcing the partnership.

Microsoft will not only build Xen support into its software, it will provide 24-hour technical support for customers seeking to get Linux virtual machines up and running under Longhorn Server and Xen.

"We've been in a dialogue with Microsoft about support for Xen for some time," noted Artale. "Xen-enabled Linux is now a first class citizen on Longhorn Server," he added.