In previous versions of Windows, upgrading a domain meant running the adprep command with several options to prepare the server for the upgrade.
A domain upgrade occurs during the role installation process, during which you first choose to add the new Windows Server 2012 to an existing domain (see Figure 4-8).
FIGURE 4-8 Adding a domain controller to an existing domain running Windows Server 2008 R2.
The next several panes in the wizard are the same as the default Configuration Wizard process, specifying the domain controller options and paths for the database, log files, and SYSVOL. Of note is the suboption underneath Paths, called Preparation Options. This pane, shown in Figure 4-9, indicates that the wizard will run forest and domain preparation commands as part of the installation.
FIGURE 4-9 The Configuration Wizard needs to prepare the forest and schema when upgrading a domain.
Once complete, the wizard installs the AD DS Domain Controller and reboots the server.
