Hey there, sysadmin community! I've been diving deep into setting up two domain controllers on our network as a failover mechanism, specifically using Ubuntu. I've been at it for about two weeks now and could really use your guidance on how to properly configure these controllers to ensure they collaborate effectively. Any insights or tips you can share would be appreciated!
3 Answers
You actually want both of your domain controllers to be active all the time. While you can assign all the FSMO roles to one DC to make it the primary, they will both handle requests by using DNS round-robin with the domain's FQDN. So, just keep them both running and let them manage the load together!
Are you familiar with the terms Primary Domain Controller (PDC) and Backup Domain Controller (BDC)? Although, I have to say, those terms are quite outdated since they haven't been relevant since Windows NT 4. Once you’re in Active Directory Native Mode, those concepts don’t really apply anymore.
You should configure both DCs with Active Directory, DNS, and Group Policy. Start by setting up one DC the way you want, then add the second DC to your forest which will allow it to replicate the first one’s data. This setup is perfect for redundancy since all changes will sync between both DCs. If you're also dealing with DHCP, set up the first one, then create a failover relationship for the second DC.

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