Where is active directory snap-in for Server 2012 R2?

Solution 1:

It's right where it has always been. The Active Directory Schema mmc snap-in works the same way in 2012 R2 as it always has.

You have to install the Remote Server Administration tools first on any server on which you want to use these snap-ins. Server Manager -> Add Roles and Features -> Features:

[X] Remote Server Administration Tools                  RSAT                           Installed
     ...
    [X] Role Administration Tools                       RSAT-Role-Tools                Installed
        [X] AD DS and AD LDS Tools                      RSAT-AD-Tools                  Installed
            [X] Active Directory module for Windows ... RSAT-AD-PowerShell             Installed
            [X] AD DS Tools                             RSAT-ADDS                      Installed
                [X] Active Directory Administrative ... RSAT-AD-AdminCenter            Installed
 -------------> [X] AD DS Snap-Ins and Command-Line ... RSAT-ADDS-Tools                Installed
                [ ] Server for NIS Tools [DEPRECATED]   RSAT-NIS                       Available
            [ ] AD LDS Snap-Ins and Command-Line Tools  RSAT-ADLDS                     Available

Then run the command:

regsvr32 schmmgmt.dll

Then start an MMC console, and then add the AD Schema snap-in.

They make it a little more difficult to get to because you can easily do irreversible damage to your AD domain with it if you don't know what you're doing.