Virtual machine snapshots are a quick way to recover from unexpected incompatibilities you may encounter when patching guest operating systems. In fact, VMware Update Manager even provides an option to automatically snapshot a VM before applying updates and then delete the snapshot after a specified amount of time.
Even if you are not using VMware Update Manager, a typical patch workflow may look something like this:
- Take VM snapshot
- Apply updates, which normally require that you…
- Reboot
- Test
- Remove snapshot
After I wrote yesterday’s post on Hyper-V snapshots, something occurred to me. The 5 steps above are only for VMware ESX. If you are using Hyper-V as your platform, you are not done yet — the snapshot differences are not actually merged until the VM is powered off.
Hyper-V administrators, please add the following steps:
- Power off VM
- Wait for merge to finish
- Power on VM
Patch Tuesday. Would you like one reboot or two?
This is really not cool. Wits Hyper-v you’ll have 2nd reboot for your VM under Windows.
This makes the unavailability of your host even longer. Thanks Microsoft. Oh my god.
I still did not figured out how to prevent the automatic reboot after update on 2008 server. It’s pretty anoying.
Cheers,
Vladan