Microsoft Virtual Server Release 2 has begun shipping to manufacturers and is due for general release in the first week of December with a new pricing model and a number of new features, most notably formal support for Linux.
Virtual Server R2 manages multiple virtual machines on a single physical computer running Windows Server.
"Technically, Linux already worked on Virtual Server, but with R2 we have formalised support, and we will continue to support Linux in the future," said Bob Muglia, who recently took over as senior vice-president of Microsoft's server and tools division.
"One thing that customers are using Virtual Sever for is to consolidate their heterogeneous environments, so this makes a lot of sense," Muglia told ZDNet UK following his keynote at Microsoft's IT Forum in Barcelona on Tuesday.
Asked whether this signalled a growing acceptance within Microsoft of the heterogeneous nature of its larger customers, Muglia said: "Any enterprise customer has a ton of heterogeneous environments, and we have always accepted that. We're just giving them what they want."
Other new features in Virtual Server 2003 include the failover of virtual operating system session from one host to another in case of hardware failure.
There is also support for clustering virtual machines on a single host, and also on different hosts over iSCSI, and the ability to run natively within 64-bit Windows. The previous version only ran on 32-bit Windows versions.
But for many, the most exciting development in virtualisation is the idea of the hypervisor, which runs at a level below any operating system, meaning that there is no need for a host operating system. This ability for software to run at a 'deeper' level than the OS is enabled at the processor level by Intel's Virtualisation Technology and Pacifica from AMD, both of which are due to feature in chips shipping next year. Gartner analyst Brian Gammage believes that, in the hardware layer at least, support for hypervisors will be mainstream by the end of the 2007.
"By end of next year, companies will find it hard to buy a PC without virtualisation support in hardware," said Gammage, speaking to ZDNet UK recently. "By the end of 2007 it will be near-impossible. That is what I call mainstream."
But hypervisor technology remains one of the features that was dropped from Microsoft's immediate operating system plans in the rush to ship Vista and Longhorn server, a gap which Gammage believes will open a window of opportunity for competitors.
Microsoft has previously said that a hypervisor for Longhorn server is planned for the second half of 2007, which means it will not be in the first release. Muglia said the desktop hypervisor is further away.
"The desktop version requires increased capabilities," Muglia said. "We need to virtualise video and similar technologies which are not necessary in the server version — the desktop hypervisor will require everything that is in the server version, and then some."
While Microsoft works on that, the likes of VMWare and the Cambridge-based open source project Xen are attempting to establish a foothold. But Muglia remains bullish. "Xen is relatively immature. We do see a lot of customers choosing VMWare, but I don't see us getting far behind."
During his keynote, Muglia demonstrated Virtual Server R2 migrating a workload from one node to another. "That is failover, and that is shipping today," he stressed,
Microsoft is also talking to hardware vendors about the possibility of delivering "virtual appliances" — virtual machines with a stripped-down operating system that do a single, very specific job. "In Longhorn we are 'componentising' the operating system, so the base is a much smaller subset that just contains the features you need, such as file sharing, DHCP and so on." Muglia said the base component will have everything necessary to run the management partition.
Virtual Server 2005 R2 Standard Edition will cost $99 (£57) with support for up to four physical processors, or $199 for the enterprise edition which support as many processors as the host operating system can handle.