Banner Message

To show a specific message on the Desktop login screen, use the Hiera key desktop::banner_message:

desktop::banner_message: 'Good morning, this is a test banner message!'

Which then looks on RHEL8 like

The default is

Please contact the service desk (phone: 4800) in case you have problems logging in.

This is only implementd for gdm (default) and not yet for lightdm (rarely used at PSI)