VNC Desktop#

With this feature you can start a VNC Desktop on Levante nodes using the jupyterlab interface.

Note

This feature is experimental and currently under active testing, we do not guarantee a full time availability. We still need to fix some issues. Please test it and report any problem to support@dkrz.de.

Overview#

../../../_images/vnc.png

How to start the VNC server#

Before starting jupyterlab#

This feature is available only for the advanced spawner. From the field User Interface list you select VNC Desktop.

../../../_images/vnc_launcher.png

A VNC desktop will start in a new tab.

How to (correctly) stop the VNC server#

  • It is important that you stop your jupyterhub session when you finish your work, the VNC Desktop will be stoped automatically.

  • Closing the window/tab does neither stop the VNC Desktop nor the jupyterhub session.

  • If you started the VNC Desktop using the advanced spawner. you need to modify the url (replace /desktop/ by /lab/tree/) to go back to jupyterlab and from there you can stop the VNC Desktop.

How to start software#

After starting the VNC Desktop, you can now launch your favorite software by using the terminal.

Example#

Note

More modules/packages/configurations can be required to start and work with a specific software.

  • ParaView

Currently, use spack.

$ spack load paraview
$ paraview

  • Matlab

$ module load matlab
$ matlab

Troubleshooting#

  • Look into the log files in $HOME/.vnc/

  • Notebook Log file jupyterhub_slurmspawner…..log

  • If you see and error like: subprocess killed, it often means a lack of memory. For e.g. Matlab requires at least 4/5 GB to start