Microsoft and open-source virtualization provider XenSource built on their unlikely alliance Tuesday, agreeing to work together to make the next version of the Windows Server operating system interoperate with Xen-enabled Linux operating systems.
Companies using Windows "Longhorn" Server and its virtualization technology will be able to run multiple instances of Windows, Linux and Xen-enabled Linux operating systems simultaneously on a single server. Microsoft will also provide technical support when Longhorn and its hypervisor become available by the middle of 2008.
"This is really good from a Xen standpoint, as it allows them to create a multi-operating system virtualization platform," said Charles King, an analyst at Pund-IT. "And it is smart for Microsoft to get with the program and acknowledge that Linux is not going to go away from the corporate data center."
In April, XenSource agreed to license Microsoft's Virtual Hard Disk format. That allows its own XenEnterprise "hypervisor" -- the technology actually used to create multiple guest operating systems, also known as virtual machines -- to import virtual machines created under Microsoft's current Virtual Server hypervisor software.
XenEnterprise is expected to be released in the third quarter of this year. With it, Xen actually competes with Microsoft, as well as market leader VMWare, a fact that Frank Artale, vice president of business development at XenSource, readily acknowledged.
"But our stated goal is to add value around the hypervisor," he said. "So we want the largest potential market for that, which is by enabling Linux as a guest OS everywhere."
Gordon Haff, an analyst at Illuminata, said it was a good move for XenSource, which is "still quite new technology that will take some time for it to prove itself out in the market."
King concurred: "For XenSource to survive, it has to support more than Linux."
Artale said XenSource will unveil some of its virtualization-related software plans later this summer, but he declined to go into specifics. While Microsoft already lets companies using Virtual Server 2005 on top of a Windows Server 2003-hosted server run multiple instances of Windows and Linux as guest operating systems, this tie-up will eventually let Longhorn deliver better performance and easier manageability, said Jeff Price, senior director of the Windows Server group.
"The core thing is that we will make Xen-enabled Linux run very well on Longhorn virtualization," Price said.
For now, there is only one Xen-enabled Linux available: Novell's SUSE Linux 10 Server, which the company officially rolled out yesterday. Red Hat is expected to follow with a Xen-enabled update to its Red Hat Enterprise Linux by year's end.
Neither company specified the exact terms of the agreement, though Artale noted that XenSource just opened an office in Redmond near Microsoft with an unspecified number of XenSource developers.
Neither company was willing to speculate how much better performance will be for instances of Xen-enabled Linux over regular Linux distributions running on Longhorn. Nor would they discuss the maximum number of guest operating systems expected to be able to run on Longhorn.
Longhorn is currently slated for release by the end of 2007. A beta of the built-in hypervisor, which creates and manages the virtual operating systems and will succeed Microsoft's existing Virtual Server 2005 product, is expected by the end of this year, Price said.
The final version of the hypervisor is expected to be out about six months after Longhorn.