Microsoft's Hyper-V does the trick

Hyper-V is finally here -- almost. With the recent delivery of Release Candidate 1, Microsoft is shifting from major engineering operations mode to cross-the-i's-and-dot-the-t's mode. The majority of the Hyper-V bits, including an ever-expanding list of supported guest operating systems, are now in place, and Microsoft customers can start migrating their test VMs into preproduction and production roles with a fair degree of confidence.

Unfortunately, the same can't be said for the company's uber-management solution for Hyper-V hosts and their VMs -- namely, Microsoft System Center Virtual Machine Manager 2008. Only recently entering public beta, MSCVMM (a mouthful of an acronym) shows promise but is hindered by the inherent limitations of Hyper-V, especially by its inability to perform live VM migrations.

First, the good news: MSCVMM introduces a new, more streamlined UI for managing Microsoft's myriad virtualization environments, which now include Hyper-V as well as the legacy Virtual Server product line. The MSCVMM console provides quick access to common tasks while allowing you to filter the view in useful ways. Major functions, like controlling VMs and managing the asynchronous Jobs engine, are broken out into logical subgroups with Vista-esque Action panes appearing on the right side of the window according to the task being performed. Each subgrouping provides copious filtering options allowing you to focus, for example, on recently added hosts or VMs in a specific state. It's a simple mechanism but one that can make a world of difference when managing a large virtualization farm.

Library science

Also helpful is MSCVMM's library for storing VM images. The cornerstone of Microsoft's transition from workgroup VM also-ran to datacenter player, the MSCVMM library makes it easy to distribute and track VMs across a growing Microsoft virtualization infrastructure. Simply select the desired VM from the MSCVMM administrator console and assign it to the desired target host server. The MSCVMM library servers and agents take care of the rest, including copying the VM image (plus any snapshots) to the corresponding physical server and bringing it online. Combined with the new Quick Migration feature -- which is basically a rapid snapshot-and-move operation, using the network as transport -- MSCVMM's maturing library model should make it easier to scale Hyper-V to levels previously reserved for the VMware Infrastructure 3 product suite.

The bad news: Unfortunately, manageability is one of the only areas where Microsoft is close to catching VMware. The company has no answer for features like VMotion, which allows for seamless movement of VMs across servers with zero downtime. Microsoft had planned such a feature for Hyper-V but had to scrap it in order to meet its planned ship date of "six months after Windows Server 2008 launches." And while Quick Migration (which leverages Microsoft Cluster Server technology) makes shifting VMs between hosts less problematic, it still requires that the virtual machine be taken offline during the transfer -- not an option for environments where high availability is a must.

Further, Hyper-V's official support for Linux as a guest OS is limited to Suse Linux Enterprise Server 10; all other Linux variants are treated as second-class citizens. Others may work, but only Suse gains installation support and extensions to improve integration (such as mouse/keyboard integration between guests and the host OS) and performance/scalability on Hyper-V. By contrast, VMware's ESX Server supports dozens of Linux variants directly by providing guest OS integration components (namely VMware Tools) to improve their performance and behavior on the ESX platform. But of course, Hyper-V's target market is consolidation of Windows servers, and nobody should be surprised that Microsoft is giving short shrift to its biggest competitive threat.