Windows Server 2012 is trying really hard to apply updates, and it could cause problems if you're delivering desktops or applications from the new platform.
Basically, Windows Server 2012 reboots without much warning and there's no way to stop it (that we know of, yet). For organizations running Remote Desktop Services
Windows Server reboot process surprises
Here's what's happening: A few weeks ago, Brian Madden and I were evaluating a Surface RT tablet. A prompt appeared saying updates were ready to be installed and we should reboot. The options presented were Restart Now and Cancel, and since we weren't done, we hit Cancel. After a few more notifications -- and subsequent Cancel pushes -- the tablet just rebooted on its own. It seems that Cancel doesn't cancel the reboot process; it just closes the window while time counts down.
What's worse is that when the tablet rebooted, there was no prompt to save your work or anything like that. It just…rebooted.
I put that experience out of my mind until last week when I noticed on Twitter that people are experiencing the same problem with Windows Server updates. Gartner Inc.'s Gunnar Berger was testing something when all of a sudden his server rebooted.
More on Windows Server 2012 RDS
What's new in Windows Server 2012 RemoteFX
Changes to Hyper-V in Windows Server 2012
A quick search of the Web turned up at least one other person having the problem -- a rebooting domain controller, no less. A domain controller is one thing, because it probably didn't take down authentication across the system. There are usually several domain controllers in an organization, so dropping one is probably only noticed by IT.
Imagine this happening to a loaded RDS server or a Hyper-V host, though. Perhaps there are preventative measures against this when the Hyper-V or RDS roles are configured on a server. Still, to have these Windows Server 2012 updates be the default, out-of-the-box behavior is troublesome to say the least.
This is a shame because the RemoteFX enhancements in Windows Server 2012 are quite good. Now, you might want to consider if it's worth moving to the new platform if you have to deal with unpredictable reboots. I'd say probably not. Keep that in mind as you evaluate moving off Windows Server 2008 or anything prior to that version.
A workaround for Windows Server 2012 updates
Fortunately, it appears you can put a Band-Aid on this problem by turning off the Windows Update Service. Of course, doing so means you no longer receive automatic updates, at least not through conventional means. It's up to you whether it's better than having the rug pulled out from under your servers on a regular basis. (Most organizations wouldn't have automatic updates turned on in production anyway, so maybe this isn't a big deal.) It's possible you could find a way to script around it by only turning on the Windows Update Service in a scheduled maintenance window when you want to apply updates.
Just what impact this issue has remains to be seen, but the fact that it automatically happens without the ability to intervene is enough to cause concern. It would seem to be a safe bet that Microsoft will address the automatic Windows Server 2012 updates in a service pack, but that's a ways out since Server 2012 was just released. Until then, use caution when delivering desktops or applications via Windows Server 2012.