Migrate DNS role from DC TO DC

Question

Hello,

I am doing a project for a client to upgrade DCs from Server 2k12 to Server 2k22. I will be building 2 new Domain controllers (2k22) to replace Old DCs (2k12).

The old DCs have DNS role on them as well, can i please get some guidance on things i need to take care of or steps to follow while migrating the role. to avoid any complications.

Also do i need to make any changes in DNS records or name servers or zones as part of post meta data cleanup process.

Thank you

Answer 1

Hello Bhatt,

Thank you for posting in Q&A forum.

Based on the description, I understand you have two 2012 DCs (also they are 2 DNS servers). Now you want to replace the two DCs (DNS servers).

The recommended way to upgrade Windows Server 2012 domain controllers to 2022 domain controllers is adding new 2022 server to domain and promoting this 2022 server as Domain Controller, we do not recommend performing in-place upgrade the OS of 2012 Domain Controller from 2012 to 2022.

If you want to upgrade the operating system of Domain Controller from 2012 to 2022, the minimum requirement to add one a domain controller of one of Windows Server 2022 is a Windows Server 2008 functional level. The domain also has to use DFS-R as the engine to replicate SYSVOL.

Step 1
You should check SYSVOL replication type. If it is FRS or DFSR.

Here is checking method via registry: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\DFSR\Parameters\SysVols\Migrating Sysvols\LocalState registry subkey. If this registry subkey exists and its value is set to 3 (ELIMINATED), DFSR is being used. If the subkey does not exist, or if it has a different value, FRS is being used.

If it is DFSR, that is OK.

If it is FRS, you should migrate from FRS to DFSR first. For how to migrate SYSVOL from FRS to DFSR, we can refer to the following article.

qUICKLY Explained: Migrate Your SYSVOL Replication from FRS to DFSR https://blogs.technet.microsoft.com/qzaidi/2012/01/16/quickly-explained-migrate-your-sysvol-replication-from-frs-to-dfsr/

Step 2

Before we do any changes to our AD environment, we had better to check our AD environment health. So we can try the following steps:

1.We need to check if all the DCs works fine, we can run Dcdiag /v on each DC to check. 2.Run Repadmin /showrepl and repadmin /replsum and repadmin /showrepl * /csv >c:\repsum.csv on PDC to check AD replication status if you have multiple DCs in your domain.

Step 3
1.Add new 2022 server to the existing domain.

2.Promote this new 2022 server to Domain Controller (add AD DS role and DNS role).

3.Also make this new 2022 DC as GC.

4.Check the health status of new DC and old DC and AD replication status (if you have more than one DC) followed Steps 2.

5.If you have more than one Domain Controllers to migrate from lower OS level (2012) to higher OS level (2022), please repeat 1-4 within Step 3.

6.After all DCs have migrate from lower OS (2012) to higher OS (2022), transfer FSMO roles to the new 2022 DC if needed. You can check whether you have successfully transferred the FSMO roles by running the command as administrator on any DC: netdom query fsmo

7.Raise forest functional level and domain functional level if needed.

How to raise Active Directory domain and forest functional levels:

https://support.microsoft.com/en-us/help/322692/how-to-raise-active-directory-domain-and-forest-functional-levels

8.Because old 2012 DC was a DNS server, update the DNS client configuration on all member workstations, member servers, and other DCs that might have used this DNS server for name resolution. If it is required, modify the DHCP scope to reflect the removal of the DNS server.

9.Because old 2012 DC was a DNS server, update the Forwarder settings and the Delegation settings on any other DNS servers that might have pointed to the old 2012 DC for name resolution.

10.Migrate all other roles on old 2012 DC to new 2022 DC (or other member servers) if you have or if you need.

11.After you transfer FSMO roles and update all DNS settings and migrate other roles if you have. And after a period of time, if everything is OK, we can consider demoting the old 2012 DCs if needed.

I hope the information above is helpful.

If you have any questions or concerns, please feel free to let us know.

Best Regards,

Daisy Zhou

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