Graphical Applications

Graphical Applications Using NoMachine NX

To provide for remote use of graphical applications on the cluster, we've installed NoMachine NX on the login hosts. To use it,

Download and install the free NX Client. (Windows users should install the optional font packages.) The NX Client uses SSH behind the scenes; see.
After installing the client, you'll need to install a public key from one of the login nodes:
1. Copy /usr/NX/share/keys/default.id_dsa.key from one of the login nodes to your local machine (it doesn't matter where).
2. In the NoMachine client, choose Configure..., then Key..., then Import. Choose the default.id_dsa.key you just downloaded. Choose Save.
When you log in the first time, you'll see a window with a number of configuration options. Under "Desktop", choose "Unix", either "KDE" or "GNOME", and the appropriate type of connection you have to the Internet. (Users on the Argonne network should use "LAN".)

You should be able to use interactive GUIs with NX even over a DSL or cable connection. Please contact us if that's not the case.

Terminating and Disconnecting

When you quit an NX session, you can either terminate it or disconnect from it. Terminating it will close all your running programs. If you discconnect you can reconnect later to the same session.

If you close the NX client window, you'll be given a choice of terminating or disconnecting.

Reconnecting

If you want to reconnect to an NX session, you'll have to log in to the same login node on which it was started. To do this, instead of using 'login.tracc.anl.gov' as the server host, specify the login node you want to connect to.

Problems

You may see the error message "Error activating XKB configuration" when you start a new session. This can be ignored, but if you want to get rid of it, then: from the Applications menu, go to Preferences -> Keyboard, then the Layouts tab, and click Reset to defaults. This should only need to be done once.

If the NX client stops working for you, log in with SSH, then try moving the .nx directory in your home directory out of the way:

cd; mv .nx .nx.bak

If you get errors similar to this:

Warning: Cannot convert string "-*-courier-medium-r-*-*-*-120-*-*-*-*-iso8859-*" to type FontStruct

you need to install the optional font packages for Windows from NoMachine.