Unattended Installation of Active Directory

Daniel Petri

Jan 8, 2009

How do I automatically upgrade a server to a domain controller during installation?

You can automatically run DCPROMO during an unattended installation. Enter the command

dcpromo /answer:%path_to_answer_file%

You’ll see a dialog box that says DCPROMO is running in unattended mode. Then, the machine will reboot.
You can also add DCPROMO to the unattended file that‘s used to install your server.
The Microsoft Windows 2000 Resource Kit details the DCInstall section’s parameters in the file Unattend.doc:

Value	Explanation
AdministratorPassword	The new password for the domain Administrator account
AutoConfigDNS	Specifies whether the wizard should configure DNS
ChildName	Name of the child part of the domain
CreateOrJoin	Specifies whether the domain will join an existing forest or create a new one
DatabasePath	Location for the Active Directory database
DNSOnNetwork	Used when a new forest of domains is installed and no DNS client is configured on the computer
DomainNetBiosName	NetBIOS name for the domain
IsLastDCInDomain	Only valid when demoting an existing domain controller to a member server
LogPath	Path for the Directory Service (DS) logs
NewDomainDNSName	Name of the new tree or when a new forest is created
ParentDomainDNSName	Specifies the name of the parent domain
Password	Password for the username used to promote the server
RebootOnSuccess	Specifies whether an automatic reboot should be performed
ReplicaDomainDNSName	Name of the domain to be replicated from
ReplicaOrMember	Specifies whether a Windows NT 4.0 or 3.51 BDC being upgraded should become a replica domain controller or be demoted to a regular member server
ReplicaOrNewDomain	Specifies whether the machine is a new domain controller in a new domain or a replica of an existing domain
SiteName	Name of the site (Default-First-Site by default)
SysVolPath	Path of SYSVOL
TreeOrChild	Specifies whether entry is a new tree or child of existing domain
UserDomain	Domain for the user being used in promotion
UserName	Name of the user performing the upgrade

Because the DCPROMO process occurs after setup, the created answer file must be called $winnt$.inf and copied to the ‘system32 folder. You need to add the following text to the GUIRunOnce section of the unattended Setup answer file:

[GUIRunOnce]
"DCpromo /answer:%systemroot%\system32\$winnt$.inf"

After the DCPROMO process completes, DCPROMO removes password information from the $winnt$.inf file. To make this process easier because the RunOnce command doesn’t execute until someone logs on to the computer, you can add the following text to the unattended answer file.

[GUIUnattended] Autologon = yes ; automatically logs on the administrator account AutoLogoncount = n ; number of times to perform auto-admin logon
Don‘t use items such as %systemroot% or %windir%, because the unattended installation process doesn’t understand them.
You can just create a DCInstall section directly in your unattend.txt file to avoid having multiple unattended setup files. Enter text such as the following:

[DCInstall]
AdministratorPassword = password
CreateOrJoin = Create
DomainNetBiosName = dpetri
NewDomainDNSName = dpetri.net
RebootOnSuccess = Yes
ReplicaOrNewDomain = Domain
SiteName = "Lab"
TreeOrChild = Tree

My example script would create a new forest with the domain dpetri.net at the top and the new domain controller in the site Lab. The SYSVOL, logs, and Active Directory (AD) files would be in the default locations. The new domain Administrator account password would be password.