Upgrading OS on Domain Controllers from 2012 standard to 2016 standard
Have two domain controllers and need to upgrade both from 2012 standard not 2012 R2 to 2016 Standard. Wanted to see if anyone had issues. Pretty sure I upgrade the one server and promot it, then upgrade the other server. Both are virtual, so I will have snapshots done.
Should not be a problem but do not do an in-place upgrade. In-place are risky and possibilites of corruption carry-forward.
I'd check that domain functional level is at least 2003, then use dcdiag / repadmin tools to verify health correcting all errors found before starting. Then stand up the new 2016, patch it fully, license it, join existing domain, add active directory domain services, promote it also making it a GC (recommended), transfer FSMO roles over, transfer pdc emulator role, use dcdiag / repadmin tools to verify health, when all is good you can decommission / demote old one and move on to next one. Also at some point either before or after I'd recommend migrating sysvol replication from older FRS technology to DFSR