Using DCPROMO in Unattended installations or Server Core.

To use DCPromo, We need a .txt file with configuration apply to server.

For Example add un DC server in a site named NewYok:

[DCINSTALL]
UserName=MyAdminUser
UserDomain=Mydomain
Password=Password123
SiteName=NewYork
ReplicaOrNewDomain=replica
ReplicaDomainDNSName=mydomain.loc
DatabasePath=N:\ADDS\NTDS
LogPath=N:\ADDS\NTDS\Log
SYSVOLPath=N:\ADDS\SYSVOL
InstallDNS=yes
ConfirmGC=yes
SafeModeAdminPassword=Password123
RebootOnCompletion=yes

Execute in command Prompt:

DCPROMO /unattend:C:\MyUnattendFile.txt

See:
http://support.microsoft.com/kb/947034/en-us