AD Forest Level Upgrade Procedure 2003>2012R2

We are in the process of upgrading our single domain forest from 2003 to 2012R2. We have several site- (On=On-Prem and AWS)

Currently we have all 2008 Domain Controllers in a 2003 Forest Level. We ran Forest Prep already.  Once forest level is raised I will run DCDiag to make sure all looks good.

Once on 2008 Forest level, can I promote a 2012R2 server to Domain Controller?
Once on the DC role is on a 2012KR2, can the forest level be upgraded to 2012R2 from 2008?
Is there any Forest preps that needs to be done in between?
Any one know of any "Gotcha" during this process?
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Cliff GaliherCommented:
You can add 2012 R2 domain controllers. It will do any schema updates when it is promoted. So yes the ad prep /forestprep gets run, but on 2013 it is no longer a manual step. But since it is a schema change, backups should still be made first.

Your forest and domain functional levels can only be as high as the LOWEST version DC. So in your scenario you could not raise the functional level to 2012. Not using less and until you retire the 2008 DCs.

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
RobertSystem AdminCommented:
Yes you join a 2012 R2 server to the domain and make it a DC even when the functional level is 2003.
You just cant raise the functional level to 2012 if you still have domain controllers running at a lower level.

So if you still have 2008 DC's don't raise the functional level to 2012.

If you have not already done so I would recommend reading this article.
GGHCAuthor Commented:
Thank you for quickly answering my concerns and providing guidance!
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Active Directory

From novice to tech pro — start learning today.