VNC on Polaris

Overview

VNC (Virtual Network Computing) is available on Polaris to run graphics applications. To avoid slowing down login nodes, please run VNC on compute nodes.

Password for VNC

Create a unique password for VNC and store it in a secure directory.

Setting the password:

vncpasswd [file]

Omitting [file] will save the password to ~/.vnc/passwd.

VNC Launch Script

Create a script for your preferred shell (e.g., Bash) with the following commands:

#!/bin/bash

Xvnc -PasswordFile ~/.vnc/passwd -geometry 1920x1080 :0 &
sleep 2
icewm --display=:0 &
xterm -display :0 &

Launching the Script

Start an interactive session using qsub with the -I option.
Run the VNC launch script on the compute node.

Establishing an SSH Tunnel

On another terminal type:

ssh -v -N -L 5900:x3005c0s7b0n0:5900 yourusername@polaris.alcf.anl.gov

where x3005c0s7b0n0 is the name of your Polaris compute node. The default TCP port for VNC is 5900. Edit as needed.

Connecting to Your VNC Server

Install a VNC client on your local computer.
Run the client and connect to localhost:5900.
Enter your VNC password.
Launch your graphics application from the xterm

Tips

Keep the SSH tunnel terminal open during your session.
Adjust the SSH tunnel command as needed for your setup.
If for any reason you need to restart the VNC server and get error messages, try:
```
killall Xvnc icewm xterm
```