So we are currently have 4 2012R2 domain controllers with IDMU (Identity Management for Unix) and NIS server role installed. For NIS server role, one DC is in master mode, other 3 DCs are in subordinate mode.
We need to upgrade all Windows domain controllers to Server2019, meaning no IDMU and NIS will be supported any more, they have been removed since Windows Server 2016.
To be able to upgrade to Server2019, the NIS server role must be removed.
If you try upgrade to Windows Server 2016 from a Windows Server that runs any of the Identity Management for Unix (IDMU) components, the upgrade will stop and you will be prompted to remove the IDMU components
According to this link When you remove the master NIS server, another subordinate server must be assigned as master
If you remove Server for NIS while it is running on a master server, you must verify that another server is assigned the tasks of the master server. If other Windows-based subordinate NIS servers are in the domains supported by the master server that you remove, you must assign one of these servers the role of master server.
So here the questions come,
I can remove 3 NIS subordinate servers first and upgrade them to 2019, but what I do to upgrade the last domain controller? I have no other NIS server in the domain to assign as the master, other 3 domain controllser are now server 2019 which has no NIX server role anymore.
what happens to "NIS domain" created in server2012, there is no such attributes in server 2019.