In this step-by-step Screencast we demonstrate how to add an additional Windows 2012 Domain controller to an existing Server 2012 forest. 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. One of the best practices is to have at least two DC in a domain, for a redundancy.
Fig.1
Fig.1 One of the best practices is to have at least two DC in a domain, for a redundancy.
After we add Active Directory Domain Services role, we make sure that our server is ready for promotion, using DCDIAG utility
Fig.2
Fig.2 Check whether server 2012 is ready for promotion .
It is crucial, to validate the result of adding a new Server 2012 Domain Controller to your domain. We go through the most important checks and tools that you will need, in case you hit a problem
Fig.3
Fig.3 Add Server 2012 DC – DirectoryServices-Deployment.log .

Finally, we discuss the distribution of FSMO roles, and collocate some of the master roles to our new Server 2012 DC.
Fig.4
Fig.4 Server 2012 – Move FSMO Roles
For your convenience, we have published the text file with the commands which we are using in the Screencast here .

Step 1 We start by configuring and preparing our new Server 2012 for DC promotion.

Step 2 In this step, we check whether our new server is ready for DC promotion and run Active Directory Domain Service configuration wizard.

Step 3 In the last step, we validate Domain Controller promotion. We go through the most important tools and practices to check the status of the new Domain Controller. As an optional step, we discuss the FSMO roles distribution and collocate some of the master roles on the new Server 2012 Domain Controller.