You do not HAVE to have ADDS for a standalone Remote Desktop Services host in 2012. Although Microsoft has made it much more difficult, you can configure everything via powershell and local group policy. Active Directory is only necessary if you wish to use the GUI functionality as they assume everyone will want to manage a collection of RD Session Hosts.
To setup a RD Session Host without ADDS do the following:
- Add Roles\Features -> Role based or feature based install
- Select Role Remote Desktop Services
- For Role Services, choose Remote Desktop Licensing and Remote Desktop Session Host
Now configure\install licenses using RD Licensing manager
Now configure Remote Desktop Session Host using local group policy as follows
- Run gpedit.msc -> Local Computer Policy -> Computer Configuration -> Administrative Templates -> Windows Components -> Remote Desktop Services -> Remote Desktop Session Host -> Licensing. (There are two settings we must enable and configure)
- Configure "Use the specified Remote Desktop license servers" (localhost if using same host as licensing server)
- Set the "Remote Desktop licensing mode"
- Force gpupdate. cmd prompt -> gpupdate /force
Sources: Source 1 Source 2