Virtual Desktops

Use WebVNC or DCV to run GUI applications on HPC resources.

	WebVNC*	DCV
use case	all GUI applications that do not need OpenGL	only GUI applications that need OpenGL
clusters	all*	Visualization (Vis)

Note

WebVNC has GL support at the visualization nodes on cluster named Visualization (Vis).

Launch a Virtual Desktop

Step	WebVNC	DCV
1	Navigate to https://jupyterhub.hpc.tu-dresden.de. There is our JupyterHub instance.
2	Click on the "advanced" tab and choose a preset:
3	Optional: Fine tune your session with the available Slurm job parameters or assign a certain project or reservation. Then save your settings in a new preset for future use.
4	Click on Spawn. JupyterHub starts now a Slurm job for you. If everything is ready the JupyterLab interface will appear to you.
5	Click on WebVNC to start a virtual desktop.	Click on DCV to start a virtual desktop.
6	The virtual desktop starts in a new tab or window.

Demonstration

Using the Quickstart Feature

JupyterHub can start a job automatically if the URL contains certain parameters.

	WebVNC	DCV
Examples	WebVNC	DCV
Description	cluster vis, 1 Node, 1 CPUs with 1,5 GB RAM, 1 GPU	cluster vis, 1 Node, 2 CPUs with 2 GB RAM per core, 1 GPU
Link creator	Use the spawn form to set your preferred options. The browser URL will be updated with the corresponding parameters.

If you close the browser tabs or windows or log out from your local machine, you are able to open the virtual desktop later again - as long as the session runs. But please remember that a Slurm job is running in the background which has a certain time limit.

Reconnecting to a Session

In order to reconnect to an active instance of WebVNC, simply repeat the steps required to start a session, beginning - if required - with the login, then clicking My Server, then by pressing the + sign on the upper left corner. Provided your server is still running and you simply closed the window or logged out without stopping your server, you will find your WebVNC desktop the way you left it.

Terminate a Remote Session

Step	Description
1	Close the VNC viewer tab or window.
2	Click on File > Log Out in the JupyterLab main menu. Now you get redirected to the JupyterLab control panel. If you don't have your JupyterLab tab or window anymore, navigate directly to https://jupyterhub.hpc.tu-dresden.de/hub/home
3	Click on Stop My Server. This cancels the Slurm job and terminates your session.

Demonstration

Note

This does not work if you click on the button Logout in your virtual desktop. Instead this will just close your DCV session or cause a black screen in your WebVNC window without a possibility to recover a virtual desktop in the same Jupyter session. The solution for now would be to terminate the whole Jupyter session and start a new one like mentioned above.