Migrating the primary domain controller from Windows Server 2008 R2 to Windows Server 2012 R2

I want to describe how I upgraded the primary domain controller (PDC) from Windows Server 2008 R2 to Windows Server 2012 R2. Seasoned, hardcore admins probably won't need this article: it covers things that are obvious to them. However, for ordinary jacks-of-all-trades this note (too small to be an article) may well be useful.

I have a small network at my disposal. There is a domain with just 1 domain controller running Windows Server 2008 R2. The goal is to upgrade the domain controller without bringing the domain down. My workstation runs Windows 8.1. This matters, because starting with Windows 8 Hyper-V has been included in the client editions of the operating system.

My overall plan was roughly this:

1. Create a virtual machine and install Windows Server 2012 R2 on it.
2. Join it to the domain.
3. Add the AD DS role to the server.
4. Make it the infrastructure master, PDC, RID master, schema master and naming master.
5. Remove the AD DS role and all other roles that replicate between domain controllers from the server being upgraded.
6. Remove the server being upgraded from the domain altogether.
7. Install Windows Server 2012 R2 on it (formatting the disks first).
8. Add the AD DS role to the new server.
9. Make it the infrastructure master, PDC, RID master, schema master and naming master.
10. Remove the AD DS role and all other roles that replicate between domain controllers from the virtual server.
11. Remove the virtual server from the domain.
12. Delete the virtual machine.

So it's all very simple. While the real server is out of action, the virtual server performs its functions.

You can find out who is who in the domain with this command:

netdom query /domain:%userdomain% fsmo

How to transfer the domain controller roles:

This is done with the ntdsutil command. We will run it on %servername%, i.e. the server we want to make the main one.

After starting the utility, enter these incantations:

1. roles - we are going to manage the NTDS role owners
2. connections - we are going to choose which AD DS to connect to
3. connect to server %servername% - connect to the server %servername%.
4. q - leave the connections mode
5. ? - see what we can do
6. transfer infrastructure master
7. transfer naming master
8. transfer PDC
9. transfer RID master
10. transfer schema master
11. leave the utility by typing q twice.

Of course, once the (now upgraded) domain controller is back in its place, you need to deploy on it all the roles that were deployed there before. You did remember to make a backup, didn't you?