What to Do When a Job Fails with a Bad X11 Display? (NetworkComputer & FlowTracer)

Goetz Leonhardt
Goetz Leonhardt New Altair Community Member
edited February 2023 in Altair HPCWorks

Sometimes jobs fail and show the following error:

Bad X11 Display

VOV_JOB_XTERM: Cannot use DISPLAY=vl-c-abpate-gridsdca:12.0 with XTERM=/usr/bin/xterm: child process exited abnormally

This is not a tool error, but an error generated by FlowTracer. When the vovproject is created, the display for xterms is set. You need to check it.

  • It is stored in the property X11_DISPLAY on set 1. 
  • The display can be retrieved with vovprop get 1 X11_DISPLAY.

If the display has been changed, xterms and other windows may show different display variables. This may be because of a new remote connection. In this case, the user needs to change the display variable to a new display.

vovprop set 1 X11_DISPLAY "new display"

Find out the current display setting by echoing the content of your env variable $DISPLAY, in csh echo $DISPLAY. If you are running as a different user, you also need to open permissions on your display, for the job to open a display. A basic command is:

xhost +

There may be more sophisticated methods in place, involving settings of X11_AUTHORITY, and other methods. Note that we currently do not support remote displays using ssh -Y.

The display could no longer be available if the current user does not have access permissions. To debug this, try another command that opens something. Commands commonly available that open a new window in Unix include:

xclock

xterm

You can also override the DISPLAY variable for a specific job by using the vovconsole GUI. To do so, perform the following steps:

  1. Double-click the job to open the NodeEditor and select tab Execution & Impact.
  2. Insert the available DISPLAY in X11 Display right above the Default X11 Display.
  3. Retrace the job after saving the new setting.
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