Chapter 14. Session Management

14.1. What Is GDM?

The GNOME Display Manager (GDM) is a graphical login program running in the background that runs and manages the X servers for both local and remote logins.
GDM is a replacement for XDM, the X Display Manager. However, GDM is not derived from XDM and does not contain any original XDM code. In addition, there is no support for a graphical configuration tool in GDM, so editing the /etc/gdm/custom.conf configuration file is necessary to change the GDM settings.

14.1.1. Restarting GDM

When you make changes to the system configuration such as setting up the login screen banner message, login screen logo, or login screen background, you need to restart GDM for your changes to take effect.

Warning

Keep in mind that restarting the service forcibly interrupts any currently running GNOME session of any desktop user who is logged in. This can result in users losing unsaved data.
To restart the GDM service, run the following command:
# systemctl restart gdm.service
For more information about managing services on Red Hat Enterprise Linux 7, see the System Administrator's Guide.

14.1.2. Displaying results of GDM configuration

To display results of the GDM configuration, run the following command:
             $ DCONF_PROFILE=gdm gsettings list-recursively org.gnome.login-screen