C H A P T E R 7 - Gnome Display Manager

C H A P T E R 7

Gnome Display Manager

The Gnome Display Manager (GDM) is responsible for logging users into your system and starting their sessions (an X11 server plus applications). It is typically used to manage the console on a system that is configured with a graphics device, but it may be used to manage other displays attached to a system as well.

Unfortunately the version of GDM that is supplied with your system is not able to work in a Sun Ray environment. Therefore, the Sun Ray server software includes a GDM that has been enhanced with the ability to manage Sun Ray devices. This enhanced GDM is otherwise identical to the GDM it replaces, and can still be used to manage the console and/or other displays.

Installation

During the SRSS installation process, you will be asked whether the installation script should remove the existing GDM from your system. You must answer "yes" to this question in order to continue with the SRSS installation. SRSS will then remove the old GDM from your system and install the Sun Ray-enhanced version. If you answer "no", the SRSS install process will be aborted.

Since the existing GDM will be removed during SRSS install, it is recommended that you not use a GDM-controlled display to do the install. Use a telnet session into the server, or a virtual terminal.

Caution - Sun Ray Server Software requires its own Sun Ray-enhanced Gnome Display Manager. If you update your system with a newer GDM, SRSS will not be able to run, and DTUs with 2.0 or newer firmware will display the 26D icon.

Tip - If you are using an automatic update system, such as Red Hat's up2date, you may wish to alter your configuration files to ignore GDM.

Uninstallation

If you need to remove the SRSS software, you will be asked whether the Sun Ray-enhanced GDM should remain on your system. If you answer "no", be advised that you may have to install the original GDM RPM if you want non-Sun Ray displays, such as the console, to be managed.

Configuration

The Sun Ray GDM is based on version 2.4.4.7. If you have already upgraded your system to a newer version of GDM, the Sun Ray version may not have all the features you expect.

Sun Ray installation will remove the current GDM from your system, including its configuration file, /etc/X11/gdm/gdm.conf (or /etc/gnome2/gdm/gdm.conf on Suse systems)

Therefore, if you have modified to your gdm.conf configuration, backup the file before installing SRSS. You may wish to reapply your changes to the gdm.conf that SRSS installs.

Tip - Do not simply put your old gdm.conf in place of the SRSS-installed one, Sun Ray Server Software will not work correctly.

The default configuration for GDM is to manage DISPLAY 0 (zero) on the console. If you do not wish to start an X11 server on the console, edit /etc/X11/gdm/gdm.conf and remove DISPLAY 0 from the servers section.

Gnome Display Manager Privileges

Many Linux systems come configured with liberal administrative privileges for non-root users. You most likely do not want these privileges offered to users who login using a Sun Ray. Please review the man pages for pam_console, console.perms, and console.apps. It is also a good idea to edit the /etc/security/console.perms file to remove display numbers from the definition of console. If a definition exists for xconsole, it should be removed entirely.

For example, a line that reads:

<console>=tty[0-9][0-9]* vc/[0-9][0-9]* :[0-9]·[0-9] :[0-9]

should instead read:

<console>=tty[0-9][0-9]* vc/[0-9][0-9]*

And a line such as:

<xconsole>=:[0-9]·[0-9] :[0-9]

should be removed altogether.