The remote desktop service makes it possible to run graphical applications on the Fram system with reasonable performance over the network. The service provides a simple Linux desktop based on the very lightweight XFCE desktop environment (https://www.xfce.org/). Currently (Aug. 2018) the system has no hardware acceleration so running advanced 3D rendering applications will probably not have adequate performance.
Neccessary client software¶
Although it is possible to run the desktop in a web-browser (https://desktop.fram.sigma2.no:6080 or https://desktop.saga.sigma2.no:6080)it is recommended to use a VNC client as it gives better performance and user experience. The recommended VNC client is TigerVNC which can be downloaded from https://tigervnc.org/ (Many Linux distros have tigervnc in their software repos).
Using the service¶
Start TigerVNC and give
desktop.saga.sigma2.no:5901 as the server to connect to. You will then be presented with a graphical login window where you can fill in username and password on Fram.
Cannot connect to server¶
The service is blocked outside the academic network in Norway, e.g. UNINETT, universities and colleges. It is possible to use ssh-tunneling to connect from the outside world:
Windows with Putty¶
Open cmd.exe to get a DOS prompt and run
plink.exe -L 5901:localhost:5901 USERNAME@desktop.fram.sigma2.no
localhost:5901 as the server address. (The space after -L must be there) If you want to avoid typing you can create a .bat script with the correct plink command.
Example: Edit in notepad and save it to a location where you can click on it, e.g the desktop. Do not use word to edit this:
# Create ssh tunnel to fram from the outside world. # Use localhost:5901 as the server address in the VNC client. # Change USERNAME to the username on fram. plink.exe -L 5901:localhost:5901 USERNAME@desktop.fram.sigma2.no
Linux/MAC/Windows with OpenSSH¶
Run the command
ssh -L5901:localhost:5901 USERNAME@desktop.fram.sigma2.no
(or saga) and use
localhost:5901 as the server address.
As stated above we recommend to use the TigerVNC client for performance and security reasons. If you cannot use this client you can connect to the remote desktop using another port number, 6901, on fram that is blocked by the firewall and only allows connections from within the Fram cluster:
ssh -L6901:localhost:6901 USERNAME@desktop.fram.sigma2.no
Then you can connect to
localhost:6901 with your VNC-client.
Slurm jobs with DISPLAY export (
srun -x) doesn’t work¶
A relogin to localhost with display export helps. In a terminal window run
ssh -X localhost sbatch -x .......
We have no idea what is the cause of the problem or why the workaround helps. Just some Linux magic to please the system gods…