A few days back I gave the strongest hint that I could without breaking any NDAs that Microsoft’s Windows virtualization product group were about to release something special . I couldn’t say what at the time but it’s no longer a secret – RC1 of Hyper-V is available for download.

This second release candidate is expected to be the last before the final product ships although, as for when that will be, the only public commitment that Microsoft has made is that it will ship within 180 days of Windows Server 2008 RTM (I think that works out as 2 August 2008). Personally, I don’t think we’ll have to wait that long, although it should be said that I have no information to back this up.

Unfortunately, the current beta of System Center Virtual Machine Manager (SCVMM) 2008 is not compatible with Hyper-V RC1 although I understand that the product team are working on a fix and, to be fair, that’s one of the perils of running pre-release software. As is the fact that I need to collapse all my virtual machine snapshots before upgrading my Hyper-V hosts – it seems that Microsoft’s previous statement that “With RC, Hyper-V is now feature complete and provides a seamless upgrade path to RTM of Hyper-V.” doesn’t include snapshots (at least the VMs themselves no longer need to be recreated as part of the upgrade).

For those who used earlier versions of Hyper-V, there is one more thing to watch out for – in RC0, Windows Server 2008 guests needed to have an update applied to support the integration components but that changes in RC1 – just use the integration services setup disk as for other operating system versions.