JUSTUS2/Visualization

Description	Content
module load	vis/tigervnc
Availability	bwUniCluster_2 | BwForCluster_JUSTUS_2
License	GPL
Citing	n/a
Links	TigerVNC Homepage
Graphical Interface	No

Description

TigerVNC is a high-performance implementation of Virtual Network Computing (VNC). VNC is a client/server application that allows users to launch and interact with graphical applications on remote machines. It is usually faster than standard X11 forwarding and thus should be used if a graphical software feels slow and has bad responsiveness.

Availability

TigerVNC is available on selected bwHPC-Clusters. A complete list of versions currently installed on the bwHPC-Clusters can be obtained from the Cluster Information System (CIS).

VNC Server

First, you have to start the VNC Server on the cluster. The startup procedure depends on the cluster and hardware you are using.

• VNC Server - bwUniCluster 2.0
• VNC Server - bwForCluster Chemistry
• VNC Server - bwForCluster Chemistry - 3D Acceleration

VNC Client

The startup script of the VNC Server should have printed out detailed instructions about how to establish a connection to the VNC Server from your local computer. These instructions depend on the operating system (e.g., Linux/macOS, MS Windows) you are using and if you work with TurboVNC Java Viewer which is a tool that can simplify the handling but needs the Java Development Kit (JDK) to run. Therefore, the next steps are divided into three cases. The commands should be executed on the local computer.

• Login using TurboVNC Java Viewer
  Needed software: TurboVNC, JDK
  Open TurboVNC Java Viewer. Go to Options... -> Security -> Gateway and fill in the parameters provided by the run_vncserver script. You can save these settings in the "Global" tab if you want to. Now you can click "OK", supply the VNC server and connect to the server. You should be prompted for your ssh password and your VNC password and after that the connection is established.

• Login using TightVNC Java Viewer
  Needed software: TightVNC
  Start the TightVNC Viewer: On Linux, open a terminal and execute the following command: $ java -jar tightvnc-jviewer.jar. On Windows, just double-click tightvnc-jviewer.jar in the Windows Explorer.
  Fill in all information given to you by the run_vncserver script (see picture below) and press connect afterward.

Close-up of bwUniCluster © KIT (Simon Raffeiner/SCC)

• Login without TurboVNC Java Viewer for Linux users
  Needed software: A VNC Client such as TurboVNC
  A SSH tunnel must be created with the command given to you by the run_vncserver script, e.g.: $ ssh -fCL 5903:localhost:5903 ul_cky67@justus2-vis01.rz.uni-ulm.de
  Start your VNC Client and connect to localhost:n, where n is the display number, using the command given to you by the run_vncserver script. E.g.: $ vncviewer localhost:3

• Login without TurboVNC Java Viewer for Windows users
  Needed software: tigervnc, Putty
  You need to start Putty and go to Connection -> SSH -> Tunnels. Fill in the parameters provided by run_vncserver. After you clicked "Add" you must navigate to Session and connect to the bwUniCluster with your username and password. Once the connection is established start the tigervnc client and connect to localhost:n where n is the display number printed by run_vncserver.

Shutdown

To exit your VNC session it is not sufficient to only close the window of the viewer, because this will not terminate the VNC server. The server will keep running and you will run into problems when you try to start a new VNC session later on. Please use the "log out" function of the desktop environment inside the VNC session, this will terminate the server properly.

Starting OpenGL programs

Starting an OpenGL program in a 3D accelerated VNC session results in an error message. In order to fix this issue and redirect OpenGL commands to the graphics card on the cluster you have to use the vglrun command like in the following example:

$ vglrun glxgears -info