upgrade to 2012 R2 or how to kill your (LAB) SCCM 2012 environment

every once in a while we do some things in System Center environment
... sometimes those things are cool and we are proud to share it with everybody around
... sometimes those things are quiet crazy, and not always worth sharing ... or are they? ;)

recently I've killed my System Center 2012 LAB while upgrading to 2012 R2 release :D

don't worry, the actual upgrade from System Center 2012 to System Center 2012 went perfectly well and this process is already covered into certain extend on the different blogs. I personally like Anoop's coverage of upgrade to SCCM 2012 R2, for example.

Any way the simple story of how i destroyed my LAB:

one day, soon after the System Center 2012 R2 and Windows Server 2012 R2 bits were released for GA i was enjoying a brain killing Change Advisory Board meeting at a customer, it had a huge agenda and i had no excuse to escape. After first 5 minutes i've realized that i was already brain dead and it'll take just a few more minutes at most to switch into a coma sleep. I had to do something to prevent insulting the customer's management...
And I've found!!! I've decided to upgrade my System Center 2012 LAB to the R2 release.
unfortunately i've got a very fast notebook with lots of RAM and SSD's and event updating both SCCM 2012 and SCOM 2012 servers simultaneously went pretty fast and without issues...
So i was where i've began fighting the fight i could never win against the coma-sleep...
Apparently my brain was  severely damaged at that time and i've decided to upgrade my LAB's OS to Windows Server 2012 R2 from Windows Server 2008 R2 i was happily using for a while...
AND I DID IT :D
it was quiet straight forward, and upgrading DC and two management server went reasonably fast.
well... usually i do create VM snapshots before i want to test even a small change, but this time i thought - it's just my own LAB, what can happen?
DC worked perfectly after upgrade...
SCOM 2012 R2 also worked perfectly after upgrade...
SCCM 2012 R2 also worked perfectly after upgrade... well, actually it seemed to work, but i've discovered quite soon that it was quiet messed up:

• Software update Point - wasn't working because WSUS service wasn't running. When i've checked, i've discovered that WSUS was just messed up after upgrade. Removing SUP and WSUS and reinstalling them didn't resolve those issues.
• PXE - wasn't working becauseWDS was messed up. After removing all DP roles and DP itself and reinstalling WDS the PXE errors in event log to be resolved.
• Management Point - MP was acting weird. After some investigation it appeared that some IIS components and settings were messed up during server OS upgrade.

After i've noticed IIS issues, i didn't even tried to resolve them... maybe because the meeting was over :D...
... instead i've deleted the VM and created a new clean W2K12_R2 build with SCCM 2012 R@ and SCSM 2012_R2 on it.

somebody may ask me - why did you do this in the first place?
the answer is as simple as it can - my other customer had actually asked me if they could perform inplace OS upgrade of they servers because they are moving all of their servers to W2K12_R2 asap.

the short answer (at least for SCCM 2012 site servers) is don't.

if you want to upgrade OS of your site server from W2K8_R2 to Win12, then perhaps you should consider using old fashioned backup and restore instead of inplace upgrade.
HOW TO UPGRADE your server OS?
just back-up your whole source site server.
get a new VM with the same disk layout and identical name and restore the ConfigMgr site to the new server.
have fun :)

By the way, do you want (or nee/must) upgrade your site server's OS from 32-bit to 64-bit?
Then this back-up and recovery is the only possible way to achieve the result.