Virtual machines are hot, and their proliferation is spinning out of control. Why the virtual-machine rush?

Easy: The "one operating system, one hardware host" rule is passé now that virtual-machine software lets companies stretch their hardware resources as far as their CPU capacity can take them.

Sessions, whether server or client, are freed from their hardware shackles. The downside is that virtual machines are creating virtual sprawl and management chaos. Each implementation behaves differently from the next, so predictability is spotty. Likewise, data backup and server availability plans have been thrown for a loop.

Makers of virtual-machine software platforms do offer some built-in methods for controlling infrastructure, but the sheer diversity of virtual-machine administration tasks have spawned a burgeoning aftermarket of products geared to reining in the mutating beast.

Some of these management suites come from virtual-machine makers -- VMware, Microsoft and XenSource (recently acquired by Citrix Systems). Virtual-machine management start-ups and traditional server-management mainstays also have jumped into the fray.

In this first of a three-part series of testing-based articles, we examine the management wares from VMware, Microsoft and XenSource, looking at features included in their base virtual-machine platforms, as well as products offered by each vendor as part of add-on management consoles for its own platform. Other tests comparing offerings from third-party virtual-machine management vendors will be published later this year.

We've identified five areas that need to be addressed to make virtual-machine management a workable venture in a large deployment: