Remote Visualization Service

A web-based Remote Visualization Service (RVS) is available on DRACO and COBRA for all the users that want to access GPU resources for visualization.

Each visualization session uses half of a visualization node (i.e., a single GTX980-1070 GPU, 16 cores and 127 GB of main memory on DRACO or a single RTX5000 GPU, 20 cores and 92 GB of main memory on COBRA) with a maximum run time of 24 hours and has access to all the visualization software (see the software page) and data available on the HPC systems.

Web Interface

To start using the service, users can login to https://rvs.mpcdf.mpg.de with their Kerberos user name and password, using a web browser that supports HTML5 (we recommend to use Mozilla Firefox or a Chrome-based browser).

Three options are available:

  1. Initialize Remote Visualization
    initializationThis step is only required the first time a user wants to access the RVS on a specific HPC system. Using the web form, the user can set the VNC password which is required to connect to running sessions later. This step also creates a folder called 'rvs' in the home of the user, where logs of the remote visualization sessions will be stored.

  2. Submit new session:
    submitting
    This page provides the form to request a remote visualization session on the HPC system. Here, users can specify parameters of the session such as the screen resolution (default 1600x800) and the length of the session (default 4 hours). Once the form has been confirmed, the remote visualization job is submitted to the batch queue on the HPC system, and a notification e-mail is sent to the user as soon as the session is ready.

  3. Connect to session:
    managing
    This page provides information about the status of submitted remote visualization sessions, including the possibility to cancel a session or connect to a running one. Remote sessions are opened in a new browser tab. The VNC password that has been specified in step one has to be entered to finally give the user access to the remote visualization session directly from the web browser.

Command line interface

Users that prefer to use a command line interface can manually initialize and request a visualization session by submitting jobs to the batch partition 'rvs' on the HPC system. The initial setup needs to be performed only once by the user via the 'setup_rvs' script as follows:

$ module load rvs
$ setup_rvs

This will create a password for the VNC connection, and the folder 'rvs' in the home directory of the user (with an automatic backup of previously existing folders with the same name) where logs will be stored. For example, to start a 4-hour long interactive visualization session, the user can then simply run the following commands:

$ module load rvs
$ sbatch --time=04:00:00 $RVS_HOME/bin/rvs.cmd

As soon as the visualization session starts on a GPU node, the user will receive a notification e-mail with instructions on how to connect via a conventional VNC software client, or via the new web interface.

Please, note that only the MPCDF authorized scripts can run on the RVS partition: scripts modified by the users will result in an immediate failure of the job.

Technical details

The web-based Remote Visualization Service at MPCDF is based on a combination of Virtual Network Computing (VNC) and WebSocket technologies.

VNC provides a method to access a virtual graphical desktop on the HPC systems via the Remote Frame Buffer protocol, thus efficiently transmitting a stream of images between the server and the client.

On the other hand, the noVNC software provides a TCP proxy between the VNC server running on the host and a browser that supports the HTML5 standard (browser capabilities can be tested at this link).

Combining this two technologies, the remote visualization service starts a VNC server for the user on the host and redirects the connection to the user web browser using the TCP protocol.

session

An example of a running session can be seen in the image above. Please note that the noVNC toolbar on the left-hand side of the browser window provides additional settings to personalize the connection, like re-scaling, full screen and a clipboard function that should be used when copying and pasting content between the user's current desktop and the virtual desktop running in the browser.

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