Half the VM reboots on Patch Tuesday

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:

1. Take VM snapshot
2. Apply updates, which normally require that you…
3. Reboot
4. Test
5. 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:

6. Power off VM
7. Wait for merge to finish
8. Power on VM

Patch Tuesday. Would you like one reboot or two?

Related posts:

1. IGT Part 5: Hyper-V snapshots are not gone until the VM is powered off
2. Hyper-V snapshots: not for production
3. VMware vSphere 4 has a Snapshot Alarm
4. Taking snapshots of VMware ESX 4 running in a VM
5. VMware Update Manager Performance and Practices