Upgrade Windows Server Core 2008r2 to 2012 In Place..Unless it's a Domain Controller

I would never recommend an in place upgrade of any Windows version, but sometimes it may be required in certain situations. Should this be necessary I figured we could take a few minutes to walk through it. Note that doing this on a Domain Controller presents additional challenges listed at the end of this article. (TLDR: Don't do an in-place upgrade of a core 2k8r2 DC to 2012)

Let's do a core upgrade from 2008r2 to 2012:

Assumptions

• Your 2008r2 Filesystem is healthy and you don't have any major issues with the services on the node. 
• Local Admin Access
• A valid license

Upgrade

1. Insert the 2012 disk in the physical machine or VM you intend to upgrade. 
2. Change directory to the disk and execute setup.exe, i.e. "j:" (ENTER) "setup.exe"





3. When prompted, choose "go online and install updates now" if you've got internet access on this machine. If not, more forward without updating. 





4. Enter your product key for this install. Most enterprise customers will either use a volume license key or datacenter key. 
5. Here you can select to either stick with the core install or install the GUI as part of the upgrade. I'm assuming that because you are upgrading the core version you'll want to stick with core. 





6. Accept the license terms. 
7. Select "Upgrade" unless you want to do a custom install. I won't cover that here since the options would be specific to your implementation.





8. At the next screen you will be warned if there are any compatibility issues; often times virtualization components will be flagged. Oft times you can ignore this warning, but be sure you read it in full and consider how easy it would be to double back now and correct the issue. 





9. The upgrade process will now proceed; there will be a few reboots. 





10. After the upgrade is complete, ensure you update virtualization components if applicable and run Windows Update. 

Upgrading a domain controller on a core installation of 2008r2 to 2012 doesn't really work without relatively major workarounds. See this Microsoft support article for more information. This fix took quite awhile to be developed, and leaves a bit to be desired. It's probably easier to do the right thing anyhow; stand up new 2012 DCs and decommission the old 2008r2 servers. After you decommission the old ones, make sure you ensure the AD sites as well as the _msdcs and primary DNS zones are cleaned up correctly. (that's an article in and of itself) There is a long discussion thread regarding this workaround on the Technet forums.

The Dreaded Black Screen of Life!

It should also be noted that the Win2012 certification exams (70-41x) are not aware of this issue. Until next time!