This section provides information specific to the Linux port of HTCondor.

The condor_kbdd on Linux Platforms

The HTCondor keyboard daemon, condor_kbdd, monitors X events on machines where the operating system does not provide a way of monitoring the idle time of the keyboard or mouse. On Linux platforms, it is needed to detect USB keyboard activity. Otherwise, it is not needed. On Windows platforms, the condor_kbdd is the primary way of monitoring the idle time of both the keyboard and mouse.

On Linux platforms, great measures have been taken to make the condor_kbdd as robust as possible, but the X window system was not designed to facilitate such a need, and thus is not as efficient on machines where many users frequently log in and out on the console.

In order to work with X authority, which is the system by which X authorizes processes to connect to X servers, the condor_kbdd needs to run with super user privileges. Currently, the condor_kbdd assumes that X uses the HOME environment variable in order to locate a file named .Xauthority. This file contains keys necessary to connect to an X server. The keyboard daemon attempts to set HOME to various users’ home directories in order to gain a connection to the X server and monitor events. This may fail to work if the keyboard daemon is not allowed to attach to the X server, and the state of a machine may be incorrectly set to idle when a user is, in fact, using the machine.

In some environments, the condor_kbdd will not be able to connect to the X server because the user currently logged into the system keeps their authentication token for using the X server in a place that no local user on the current machine can get to. This may be the case for files on AFS, because the user’s .Xauthority file is in an AFS home directory.

There may also be cases where the condor_kbdd may not be run with super user privileges because of political reasons, but it is still desired to be able to monitor X activity. In these cases, change the XDM configuration in order to start up the condor_kbdd with the permissions of the logged in user. If running X11R6.3, the files to edit will probably be in /usr/X11R6/lib/X11/xdm. The .xsession file should start up the condor_kbdd at the end, and the .Xreset file should shut down the condor_kbdd. The -l option can be used to write the daemon’s log file to a place where the user running the daemon has permission to write a file. The file’s recommended location will be similar to $HOME/.kbdd.log, since this is a place where every user can write, and the file will not get in the way. The -pidfile and -k options allow for easy shut down of the condor_kbdd by storing the process ID in a file. It will be necessary to add lines to the XDM configuration similar to

$ condor_kbdd -l $HOME/.kbdd.log -pidfile $HOME/

This will start the condor_kbdd as the user who is currently logged in and write the log to a file in the directory $HOME/.kbdd.log/. This will also save the process ID of the daemon to ˜/, so that when the user logs out, XDM can do:

$ condor_kbdd -k $HOME/

This will shut down the process recorded in file ˜/ and exit.

To see how well the keyboard daemon is working, review the log for the daemon and look for successful connections to the X server. If there are none, the condor_kbdd is unable to connect to the machine’s X server.