One of today's most interesting tidbits came from Microsoft. Bob Kelly, corporate vice president for the company's server and tools business, announced Hyper-V:
This is the official name of the server virtualization technology within Windows Server 2008 that was previously code-named "Viridian." Microsoft also announced Hyper-V Server, a standalone hypervisor-based server virtualization product that complements the Hyper-V technology in Windows Server 2008 and allows customers to virtualize workloads onto a single physical server.
"So what?!" you say. Everybody and their dog is coming out with hypervisors that can be either purchased as standalone products or embedded into servers. Besides, Microsoft is very late to the virtualization game; its hypervisor won't even be in the initial release of Windows Server 2008.
That may all be so, but Microsoft has a huge footprint in datacenters--and even more in the IT installations of smaller companies. Thus, however tardy and reluctant Microsoft's arrival to virtualization may be (Virtual Server notwithstanding), its plans and presence matter.
That makes Microsoft's decision to offer a hypervisor that's not part of the operating system striking, given that they have been the most vocal proponents of the "virtualization as a feature of the OS" point of view. As Jim Allchin, who headed Microsoft's Platforms and Services Division until the beginning of this year put it: Windows already "virtualizes the CPU to give processing." In this sense, VMs just take that virtualization to the next level. And, in fact, there's a long history of operating systems subsuming functions and capabilities that were once commonly purchased as separate products. Think file systems, networking stacks, and thread libraries.
Built-in-ness is clearly the big argument in favor of marrying server virtualization to the operating system. You're buying the operating system anyway, so there's no need to buy a separate product from a third-party.
Of course, Microsoft wants to keep the operating system relevant to users however much Oracle and others would like to subsume it. Thus it's hardly a surprise that Microsoft wants functions in the OS both to control them and to enhance the value of its most strategic product.
But sometimes the world doesn't work the way you'd like it to.
Separate hypervisors are a better match for the sort of heterogeneous environments typically found in enterprises than are those built into OSs.
There's also a major trend afoot to embed hypervisors into x86 servers, just as they are already embedded into Big Iron. Among the early system vendors to announce or preview intentions in this area were Dell, HP, and IBM. Embedded hypervisors pretty much trump any integration advantage that virtualization-in-the-OS enjoys. You can't get much more built-in than firing virtualization up when you turn the server on for the first time.
I expect that this style of delivering the foundation of server virtualization is going to become commonplace.
It will be a while before who wrote a particular hypervisor becomes a genuine "don't care" to most users (the way BIOSs are today). Standards for managing and controlling virtual machines are still nascent and the whole area is far too new for true commoditization. But it's the direction things are headed. Even Microsoft, however reluctantly, has now accepted this even while it simultaneously tries to keep as much control over its own destiny as possible.