In this step-by-step Screencast we demonstrate how to upgrade an existing Windows Server 2008 Active Directory domain to Windows Server. In the previous Screencast of Server 2012 series, we have performed a greenfield installation of a Server 2012 Domain Controller, in a new Domain/Forest.
Chances are that you already have an existing Active Directory infrastructure in place and you are planning to upgrade it to AD 2012. In this case you have two options:
– In-place upgrade of an existing Domain Controller to Windows Server 2012 (not recommended and risky).
– Add a Windows Server 2012 to the Domain and promote it as a Domain Controller (the recommended and safer approach).
While the actual Active Directory upgrade is a straight forward process – you add Active Directory Domain Services:
Fig.1 Add AD DS in Server 2012
Fig.1 Add Active Directory Domain Services in Server 2012

and promote (configure) the Windows Server 2012 as a Domain Controller:
Fig.2 Promote 2012 Domain Controller
Fig.2 Active Directory Domain Services Configuration Wizard

a real production environment requires careful planning and extensive checks before and after introducing the first Windows Server 20120 domain controller in the forest. As you are probably aware, DCPROMO has been deprecated and your main choices for configuring a new Server 2012 Domain Controller are:
– the graphical interface – Server Manager, which we demonstrate in this Screencast
– Powershell – the Active Directory Domain Services Deployment module
We start with checking whether we cover the prerequisites for upgrading to Active Directory 2012:
Fig.3 Check AD 2012 Prerequisites – Domain and Forest Level 2003
Fig.3 Active Directory 2012 Prerequisites Check

DNS plays an important role in Active Directory functionality, and we test all DCs in the forest with Domain Controller Diagnostic Utility (DCDIAG) and DNSLINT:
Fig.4 Test DNS Health
Fig.4 Test DNS Servers with DNSLINT

It is crucial to check Active Directory health and replication before you proceed with extending the schema and upgrade to a higher level:
Fig.5 Active Directory Healthcheck
Fig.5 Active Directory Healthcheck

We follow our step-by-step approach, when we prepare and promote the new server 2012 as a Domain Controller. AD forest schema extension and domain preparation is integrated into DC promotion process and we discuss in details whether and when Group Policy preparation (GPPREP) is necessary:
Fig.6 Prepare AD for Server 2012 DC
Fig.6 Prepare Active Directory for Server 2012 DC

It is important to validate the new Server 2012 DC promotion and check again AD replication and status, and we demonstrate different approaches to perform this task:
Fig.7 Validate DC 2012 Promotion
Fig.7 Validate Server 2012 DC Promotion

Finally, we move the FSMO roles to the new 2012 domain controller and reconfigure the windows time service both on the old and on the new PDC emulator:
Fig.8 Move FSMO Roles to Server 2012 DC
Fig.8 Move FSMO Roles to Server 2012 DC

For your convenience, we have published the text file with the commands we are using in the Screencast here .

Step 1 We start by checking the prerequisites for Active Directory 2012 and running DNS and AD healthcheck.

Step 2 In this step, we prepare the new Server 2012 and promote it as a 2012 Domain Controller.

Step 3 Next, we validate the promotion process and check again AD health and replication.

Step 4 In the last step, we move the FSMO roles to the Server 2012 DC and reconfigure the Windows Time Service on the old and the new PDC emulator.