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Graphical Connections to Cluster

The central cluster is utilizing StarNet's FastX software, offering enhanced speeds, background task support and capability to run on login or compute hosts. You do not need to be running a local xserver (i.e Xquartz,X11) to use this service as the rendering occurs on the host running the FastX service. You may choose to connect via Web Browser or the dedicated FastX binary clients linked at the bottom of this page. 

You may find the custom launch scripts under /software/fastx-slurm-scripts/. By default all FastX interactive jobs will run on a compute host and not on the login server. If you do not plan on running heavy compute and instead only need to view/analyze job output, you may run on the login nodes to avoid taking up a full compute host. Please keep in mind that each graphical session run on a compute host is limited to the clusters wallclock limit of 7 days. 

Getting Started. Launching via Web Console onto a Compute Node. 

  • Point your browser to
  • Accept the self-signed certification warning. (We will be obtaining a valid cert soon to avoid this warning)
  • Login with your Caltech username/password and your multi-factor authentication device attached to the account. 
  • Clicking Launch will present you some default quick-launch bookmarks, if your application is not listed there launch the 'Xterm' option and invoke your application in the graphical Xterm window. 
  • Your application will launch on a full compute node. 

Launching via Command Line onto Login Nodes. 

Launching a FastX session on the Login nodes is useful for doing lightweight graphical work while avoiding compute related charges. This should only be used for tasks such as graphical post-job analysis, editing etc. Do NOT run heavy compute jobs here. 

SSH to the login nodes. 

ssh <username>

sh /software/fastx-slurm-scripts/ --command="xterm -ls" --geometry="rootless" --name="My Xterm Session"

This will launch a graphical xterm session which will then be accessible from the FastX web portal. From the Xterm window you may launch other graphical applications. 

Now point your web browser or binary client to

Once logged in you should see the running session, clicking on it will either open the session in your current browser window or spawn a popup window. (You may see a popup notification if popups are being blocked)

Overcoming applications with graphical anomalies or resizing issues
You may find some applications have resizing or visual artifact issues when launched directly from a graphical Xterm as above. To circumvent this issue you can launch a XFCE desktop first on the login nodes and then whatever additional applications are required. 

Run the following on any login node

sh /software/fastx-slurm-scripts/ --command="xfce4-session" --geometry="1024x768" --name="xfce4"

Now point your web browser or binary client to

Once in the XFCE desktop you may expand the view by clicking the resize icon on the FastX tab at the top of the browser window. 

Launching via command line onto a Compute Node. (recommended to use Fastx web console) 
To run a compute node interactive job via interactive slurm job run the following or start via the web console. (This is the default behavior if launching a job straight from the Web GUI and not the Command line interface. 

sh /software/fastx-slurm-scripts/ --command="xterm -ls" --geometry="rootless" --name="My Xterm Session" &

FastX Video Tutorials

FastX Binary Clients (only required if you do not want to connect via web browser)