I came away from InfoWorld's Virtualization Executive Forum this week with two conclusions. First, server virtualization is definitely a big deal. This time last year, customers and ISVs still seemed to be struggling to come to terms with this new approach to deploying and managing servers; today it's full speed ahead. And, second, nowhere is virtualization hotter than in the Linux market.

When I sat down for an interview with Red Hat CTO Brian Stevens at the show, I asked him if there were any important new technologies in the forthcoming Red Hat Enterprise Linux 5 that we should touch upon. He mentioned a few initiatives and community-based efforts that are under way at Red Hat, including work on an open source, standards-based message queuing product.

But as far as RHEL 5 is concerned, he said, virtualization is the big news. Similarly, Novell made a big deal about its support for Xen virtualization with the release of Suse Linux Enterprise Server 10 last year.

It's easy to see why this technology is so exciting for Linux administrators. Virtualization can make for a more flexible datacenter by making it easier to provision and manage server instances. What's more, by driving up server utilization it can dramatically lower hardware acquisition costs.

You gain these advantages when you virtualize any OS platform. But the fact is that, as of right now, no other OS gives you as many virtualization options as Linux. From the hypervisor-based virtualization of Xen, to virtual machine implementations including VMware and KVM, to the OS partitioning approach of OpenVz, Linux lets you carve up your servers using any method available on any other platform. Take your pick.

Better still, many of these virtualization technologies are themselves open source, and some are being integrated into the stock Linux kernel, which means customers gain access to them as part of their existing support contracts with their Linux vendors. The low barrier to entry for virtualization, combined with the proliferation of options, is a tremendous win for Linux.

Think about it. Even Microsoft supports running Linux on its Virtual Server product. Why would it do that? Wouldn't an OS partitioning technology, such as that used by OpenVz or Sun Solaris, be more in keeping with the kind of homogeneous environments that Microsoft would like to see? Why would Microsoft invest its resources to support a virtual machine technology that can only open the door to Linux in the datacenter?

The answer is that Microsoft realizes that the door is already wide open, and virtualization is only going to blow it even wider. As long as it's trivial to run virtual Windows instances on top of Linux, the reverse had better be true as well.

The one ace Microsoft still has up its sleeve is the fact that it has been doing the homogeneous environment thing for so long that it's really quite good at it. Call it platform integration or call it vendor lock-in, but the fact is that it's easier to manage a network of Windows servers and desktops than one that also includes a lot of Linux -- especially if those Linux boxes are based on multiple distributions and configurations.

This is bound to change, however. In fact, it already is changing. I've discussed before how products such as Quest Software's VintelaAuthentication Services let Windows administrators manage Linux servers with familiar Microsoft tools. This year, however, the market for cross-platform management tools -- and particularly those targeted at virtualized environments -- is set to explode.

From traditional systems management software vendors such as CA, HP, and IBM, to newer companies such as Hyperic, to such niche players as PlateSpin, Virtuozzo, and Virtual Iron, the industry is turning toward solving the problems of server management like never before. Virtualization is at the heart of this trend. And because Linux and virtualization are practically synonymous, Linux customers can expect to benefit more than any other segment of the market.