Login/logoff for the Linux Cluster at PSU

At the Mont Alto campus you can use all public computers to connect to computers at University Park running under the Linux Operating System, the so-called Linux Cluster. The files/directories you have on those computers are commonly referred to as your PSU Pass Space. To login into the linux cluster the procedure below can also be performed from your home computer provided you have an internet connection. It involves two major steps of which the first step allows you to conduct non-graphical interactions with the Linux Cluster like text-editing a file, compiling, and running your own programs. All that is needed for this step is a program called ssh which you can download for free.. The second step enhances your connection to allow the exchange of graphical information including the full visiblity of the Linux (Redhat) desktop. For this step you will need a program called VNC (free) on your computer.

Login : 1. Step

After login in at any Window-driven computer in the usual way, find the SSH program and run it. In the labs in the Bookstore and Science/Technology Building you get to it :

Start → Programs → Internet Applications → Linux Cluster → SSH

Clicking on SSH will bring up a larger window. Click on the button called "Quick Connection" . As a result a small window will pop up into which you have to enter only the top two items :

  1. As "Host Name" : lxcluster.tlt.psu.edu
  2. As "User Name" : your PennState access account

Then click on "Connect". The small window will be replaced by an even smaller dialog window asking you for PennState password. Enter your password and hit either "Enter" or click on the "OK" button.

Be a little bit patient but messages should scroll by now in the bigger SSH window. Wait until something like :

[hgn@lxcluster2 ~]

bash .....]

appears on a single line following by a blinking cursor. This is called a prompt which gives you some information: i.e. hgn is my PSU userID, I am connected to computer 2 of the linux cluster, and the ~ indicates that I am in my home directory. Although you may be connected to different computers of the cluster (numbered 1,2, or 3) you will always see the same files and directories. The prompt and the blinking text cursor are also telling you that the computer at the other end is waiting for your first command. Type for example "ls" and hit the enter button, a list of files/directories should appear followed again by the prompt. At this time - given enough knowledge - you could work on the computer to your hearts content as long as no graphics is involved. For that you have to complete the instructions under Step 2.

Login : 2. Step

In order to have the full Linux desktop visible on your screen and allow the usage of graphics-bound interactions the second step has to be conducted.

After completing the first step ( and may be after executing already some Unix commands ) type in the command :

lxclustervnc

Some text will appear asking you for the screen resolution. The computers in the labs at Mont Alto run under 1024x768 and you only need to hit the "Enter" key . Wait until the line :

Would you like to cancel your vnc session now? [yes/no]

appears. For now, don't type anything in responce, just look at the messages above this line to find a line like :

Server = lxcluster3.clc-labs.its.psu.edu:1

but leave the SSH window alone (You may minize it though). Instead :

Look now for a program called VNC on your windows machine. In the labs you find it :

Start → Programs → Internet Applications → Linux Cluster → VNC

The VNC Viewer program will pop up a small window. Fill in the box labelled "Server" with the complete server name from above (lxcluster3.clc-labs.its.psu.edu:1 in this example). You can use Copy/Paste to do that, for Paste you must right-click on the dialog box of the VNC window ). The first VNC window will be replaced by a second window asking you for your PennState password. Provide it and the complete Linux desktop will appear on your screen. Hint : the above long server name will vary in between different login sessions only in exactly two places, namely the two digits ( 3 and 1 in above example ) may change.

Logging Off

Return to your SSH window. It still should have as its bottom line :

Would you like to cancel your vnc session now? [yes/no]

Simply answer "yes" and the big Linux desktop will disappear and in the SSH window the Linux prompt will reappear. Type "exit" and close off the SSH window.

Don't forget to logoff from Windows.


Zig Herzog; hgn@psu.edu My Homepage
Last revised: 08/21/08