How do I use VNC on Tigressdata?

VNC is a graphical desktop sharing system that allows users to connect to remote computers. It is advantageous because it eliminates the need to send 3D data over the network via an X-Windows environment. The instructions here describe how to connect to a remote desktop on tigressdata. You can then take advantage of the local cpu and gpu capabilities of the tigressdata machine. It is highly recommended to use this for applications that do 3D rendering.

  • Connect to tigressdata
    • ssh
  • Load the turbovnc module to enable vnc commands
    • module load turbovnc
  • Start a vnc session
    • vncserver
  • The first time you start vncserver you will be prompted to create a password to access you vnc desktops. This can be anything you like. Should you choose to change it in the future simply delete the file ~/.vnc/passwd, and the next time to start a vnc session you will be prompted to recreate a password.
    • You may choose to have a view-only password, where others can view your desktop, but keystrokes are disabled.
    • You should get an output that looks like this:

Desktop 'TurboVNC: (NetID)' started on display

Creating default startup script /home/NetID/.vnc/xstartup.turbovnc
Starting applications specified in /home/NetID/.vnc/xstartup.turbovnc

Log file is /home/NetID/.vnc/

  • You will want to note the note the session number. In the above example it is :1.
    • You can always check what vnc session(s) you have open with the "vncserver -list" command which gives an output like:

$ vncserver -list

TurboVNC server sessions:

:1 18966

  • From your local machine you will use the TurboVNC viewer to connect, but first you need to set up an ssh tunnel. This is necessary because TurboVNC is not encrypted. The session number from earlier is "n" here.
    • Linux/Mac: ssh -A -L <5900+n>:localhost:<5900+n> <user>
    • Windows - 32-bit (from a command prompt, all on one line): "C:\Program Files (x86)\TurboVNC\putty" -L <5900+n>:localhost:<5900+n> <netID>
    • Windows - 64-bit (from a command prompt, all on one line): "C:\Program Files\TurboVNC\putty" -L <5900+n>:localhost:<5900+n> <netID>
  • Example for the above session (:1)
  • You may see a message or dialog box similar to this: "The server's host key is not cached in the registry". If you do, type or click "yes".
  • Enter the password associated with your netID.
  • Now open the TurboVNC Viewer and in the VNC server box type: localhost:<n> and click connect. For example: "localhost:1".
  • Enter the password you set up when you created your vncserver session above.
  • You should now be able to see your tigressdata desktop.
  • You can close the TurboVNC viewer, reconnect at a later time, and pick up right where you left off. Just follow the procedure for connecting to a remote VNC session above.
  • If the tunnel is closed, the session will end, but your desktop will still be intact on tigressdata. Just reconnect.
  • When you are finished with a VNC session entirely, you should end it.
  • To end a vnc session
    • ssh to tigressdata
    • If you haven't already, load the turbovnc module
      • module load turbovnc
    • Check the number of your vnc session with "vncserver -list" and note the display # of the session you want to end
    • Do "vncserver -kill :<n>" where n is the number (with a colon).
      • Ex.
        • vncserver -kill :1
  • To take full advantage of the local graphics hardware of tigressdata we use VirtualGL. Note this will only work within a VNC session. The instructions here are for a terminal open on your VNC desktop.
  • Check to make sure you have the virtualgl module loaded, if not do
    • module load virtualgl
  • Start a program as you normally would but precede the command with vglrun. Some examples:
    • vglrun visit (after doing "module load visit")
    • vglrun paraview (after doing "module load paraview")
    • vglrun /usr/licensed/matlab/bin/matlab