- 1 Running X11 GUI Apps
- 2 Connection Rejected Because of Wrong Authentication Error and Solution
Running X11 GUI Apps
It is possible to run X11 GUI apps on the Hornet cluster. In general, this is not recommended and submitting batch jobs is strongly preferable. However, sometimes X11 is necessary and there are various ways to do this.
Connecting Using NX
The head node is running a NX server, so it is possible to connect with a NX client. The NX client allows you to disconnect and reconnect without crashing your apps. Note that this is beta software.
You can install an NX client (see installation instructions below) and then connect to hornet-login1.engr.uconn.edu. In your session definition be sure to specify a GNOME SESSION.
NX client for Linux
The recommended NX client for Linux is qtnx. From Debian or Ubuntu this can be installed with the command "sudo apt-get install qtnx" From Fedora, "yum install qtnx"
Connecting Using NX from OSX
The recommended NX client for OSX is OpenNX: http://opennx.net/download.html
Connecting Using NX from Windows
Running X11 Jobs
Once you have a GUI gnome session, you can run your jobs with bsub. For a single core job which uses X11, the following will work:
bsub -XF programname
Alternative NX client
An alternative NX client could be downloaded from NoMachine at http://www.nomachine.com/download.php.
Connection Rejected Because of Wrong Authentication Error and Solution
Run following command to find ownweship:
ls -l ~/.Xauthority
Run chown and chmod to fix permission problems
chown <username>:<username> ~/.Xauthority chmod 0600 ~/.Xauthority
Replace <username>:<username> with your actual username.
Make sure X11 client forwarding enabled
Make sure your local /etc/ssh/ssh_config has following lines:
Host * ForwardAgent yes ForwardX11 yes
Finally, login to remote server and run X11 as follows from your Mac OS X or Linux desktop system:
ssh -X <username>@hornet-login1.engr.uconn.edu
Still cannot get X11 working
try to remove the .Xauthority file and login again:
rm ~/.Xauthority exit ssh -X <username>@hornet-login1.engr.uconn.edu