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Sudz28-3480 avatar image
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Sudz28-3480 asked ·

Upgrading Domain Controllers 2008 R2 to 2012 R2

We appear to have 2 domain controllers in our enclave system, both running Windows 2008 R2/64-bit. They need to be upgraded or replaced by newer 2012 R2 versions of the same. Of course I realize that in-place upgrades of them are strongly discouraged, but an apparent caveat to the replacement is that the newer DC's have to retain the same server names and IP addresses (I've been told there are 'things' in the enclave that point to the DC's strictly by IP or something, and thus any changes on the name/IP for them would cause those applications to break). They are also functioning as primary/secondary DNS servers.

Based on the whole 'they need to have the same machine info' angle, I was leaning towards attempting an in-place upgrade of both DC's maybe over a weekend where user impact would be minimal. However I think in a perfect world it would be really nice to spin up two 'new' machine, get them all patched, etc., and then cut over to them. I just have no idea how I would accomplish this while still maintaining the same machine names and IP's.... is that even possible?

My apologies in advance for my lack of knowledge, I have never set up or administered a Windows DC (well, not in over a decade anyway) so I'm sure there's a ton of stuff I'm not even considering.

I did quickly run a "dcdiag /a" on the current Master DC and it seemed to pass all tests with the exception of "test SystemLog".

windows-server-migration
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1 Answer

FanFan-MSFT avatar image
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FanFan-MSFT answered ·

Hi,
Instead of the in-place upgrade , following method for your reference:

Before add the new DC:

Fully back up the 2 old DCs (DC1 also PDC,DC2) .
Make sure ecerything is working well by command :
dcdiag /test:replications
Dcdiag /v >c:\dcdiag1.log
Demote DC2(Removing AD and Domain Services Role)
Rename DC2 TO dc2-old
Asign a new ip address to DC2,
Turn off DC2-old

New server DC3,DC4
Rename DC4 to DC2,
Asign the old ip to the new dc4.
Install the Domain Services role and promote it to DC.
Same thing between DC1 and DC3.

Test the new DC is working well by the command above.
For more information ,you can refer to the following link:
https://techcommunity.microsoft.com/t5/core-infrastructure-and-security/rename-dc-to-preserve-old-name-and-ip-address/ba-p/850935

Best Regards,

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Thanks, THIS is great information and very helpful to a relative DC n00b like myself!
Many thanks, I'll report back on how the whole operation goes once I get it all planned out an execute it.
Cheers!

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