DSfW installation is a two stage process. The first part is done in YaST, where DSfW related basic changes are done. After YaST completes the configuration, the DSfW Provisioning Plugin has to be launched. This is done to complete the changes necessary to make the server behave as a domain server.
The DSfW provisioning plugin is a GUI and it requires user interaction to complete the operation. It also require access to the X server to launch the plugin.
With this script the provisioning plugin can be done with just the password inputs.