- 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
The recommended NX client for Windows is OpenNX: http://opennx.net/download.html Please download version 0.16.0.725 The configuration of the OpenNX shown as below. Make sure that you setup the red part same as that in the screenshot.
Start an X-enabled interactive SLURM job
First of all, we DO NOT RECOMMEND to run the interactive job. The responding speed will be low.
If you want to run some jobs with the interactive GUIs, it is better to submit it to the SLURM scheduler with X-enabled interactive shell:
# Make sure you are on cn65 cn01$ ssh -X cn65 # list the partitions to see which one is free cn65$ sinfo PARTITION AVAIL TIMELIMIT NODES STATE NODELIST IvyBridge* up infinite 12 alloc cn[105-116] IvyBridge* up infinite 17 idle cn[117-133] SandyBridge up infinite 6 alloc cn[72-73,81-84] SandyBridge up infinite 28 idle cn[66-71,74-75,85-104] debug inact infinite 2 idle cn[103-104] Westmere up infinite 10 resv cn[52-61] Westmere up infinite 5 idle cn[36,42,50-51,62] # You can use "-p" to select a partition # You can use "-c" to assign more cores or less cores for your job. $ fisbatch -pSandyBridge -c4 FISBATCH -- the maximum time for the interactive screen is limited to 6 hours. You can add QoS to overwrite it. FISBATCH -- waiting for JOBID 11522 to start on cluster=cluster and partition=SandyBridge FISBATCH -- Connecting to head node (cn74) cn74$
Then, you can do your work under cn74 as an example. When you finish your work, please do not forget to release the session so that the other users can use the resources. To do so:
cn74$ exit [screen is terminating] Connection to cn74 closed. FISBATCH -- exiting job
If you think 6 hours is not enough, you can add QoS in the command:
$ fisbatch -pSandyBridge -c4 --qos=stnadard #Or --qos=longrun
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 (Linux/iOS)
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 in the Hornet and login again:
rm ~/.Xauthority exit ssh -X <username>@hornet-login1.engr.uconn.edu