Hoffman2:Accessing the Cluster

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Revision as of 03:08, 9 April 2014 by Elau (talk | contribs) (Updating to include information about XQuartz and new Macs)

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Here are some of our favorite ways to access the Hoffman2 Cluster login nodes.

SSH - Command Line

The official description of how to do this is found here

SSH stands for Secure Shell and is a method of remotely logging into a computer using an encrypted connection. It is a command line tool and is available on most *nix-based operating systems with ports available for Windows.

If you are on a Mac/Linux/Unix...

Modern Macs (anything with Operating systems newer than Snow Leopard 10.6.x) no longer come with a X Window Client pre-installed.

Before doing the following steps, please install XQuartz and restart your computer.

For more information about XQuartz, read here.

  1. Open up X11/XQuartz or Terminal. Both are under Applications > Utilities on Macs.
  2. Type the command
    $ ssh -X [USERNAME]@hoffman2.idre.ucla.edu
    filling in your Hoffman2 username.
    The -X is for X11 Forwarding so that any graphics that are rendered on Hoffman2 get forwarded to the screen of your computer. A -Y flag accomplishes the same thing but does not secure the connection. Correct us if we have that switched.
  3. Press enter and type in your password when it asks for it. No characters or asterisks will show up while you type.
  4. Provided your typing was good, you will be greeted by the Hoffman2 login message and have successfully SSHd into a login node.

WARNING: Please note that in OSX 10.8 (Mountain Lion), Xorg is no longer support by Apple. Instead, use XQuarts

If you are on Windows...

  1. Go here and follow the instructions under Windows. We recommend PuTTY or Cgywin.
  2. Once you have that setup, the process is the same as if you were on a Mac or Linux/Unix machine

NX Client - GUI

The official description of how to do this is found here

The NX Client program allows you to set up a Virtual Network Computing (VNC)-like session with Hoffman2. This session will keep running even if your Internet connection drops in and out (much like screen on the command line).

PCs or Mac OS X 10.6 and earlier

  1. Go to the No Machine website and navigate to the Download tab.
  2. Find the section titled NX Client Products and click on the one for the operating system you are running.
  3. Download the appropriate installation file and install it on your computer.
  4. Once it is installed on your computer, start up NX Client.
  5. The window that appears will ask for:
    • Login -- your Hoffman2 username
    • Password -- your Hoffman2 password
    • Session -- type Hoffman2
  6. Then click the Configure... button and fill out the necessary information
    • Under the General tab
      • In the Server section
        • Host -- hoffman2.idre.ucla.edu
        • Port -- 22
        • Key -- Click this button and delete the contents of the window that appears. Open up an SSH session to Hoffman2 and run the command
          $ cat /etc/nxserver/client.id_dsa.key
          The output is the key. Copy everything that was printed out and paste it into the Key window in NX Client and click Save.
      • In the Desktop section -- Use the drop down menus to select Unix and GNOME
    • Click Save
  7. Now you can click Login on the main window and a GUI environment connection will be established with a Hoffman2 login node.

Mac OS X 10.7 and newer

  1. Go to the Download Preview section of the No Machine website ([1]). and download the NX Client 4 preview.
  2. Open the DMG that you downloaded, copy "No Machine Player.app" into your "Applications" directory and open it up for the first time.
  3. A window titled "New connection" will appear. Fill out the fields accordingly
    • Name -- Something like "Hoffman2"
    • Host -- "hoffman2.idre.ucla.edu" since this is the server you are connecting to
    • Port -- 22
    • Select "Use the NoMachine login" and click the button on the right labeled with "..."
      • In the new window labeled "NoMachine login" check the box next to "Use an alternate server key"
      • Open up a Terminal and run the following command (replacing USERNAME with your Hoffman2 username)
        $ scp USERNAME@login2.hoffman2.idre.ucla.edu:/etc/nxserver/client.id_dsa.key ~/Documents/
      • and enter your Hoffman2 password when prompted.
      • Back in NoMachine, click on the button labeled "..." and find the file you just downloaded (it is in your Documents folder labeled "client.id_dsa.key").
      • Click on the X in the top right corner to return to the previous window.
    • Click on the X in the top right corner to finish setting up the connection parameters.
  4. Double click on the connection you just created (it should be the only one in the list).
  5. A circular progress indicator will show up for a bit before giving way to an authentication screen asking for username and password.
  6. Enter your Hoffman2 username and password and click "OK" (You may also check the box labeled "Save this setting in the configuration file" to avoid retyping this in the future)
  7. A circular progress indicator will show up again until a menu appears. Select "Create a new session".
  8. In the next menu, select GNOME.
  9. After another circular progress indicator, a virtual desktop should appear.
  10. Reconnections in this client are not currently supported for Hoffman2, so please make sure to logout and close your connections properly. [2]


If your NX Client session freezes and you are unable to close it properly, open NX Session Administrator and disconnect your session from there. This freezing often occurs when your Internet connection is lost abruptly. Another possible cause for freezing is scrolling on certain Windows touchpads.

UCLA Grid Portal

The official description of how to do this is found here

We haven't used this one much yet, but we'll be trying it out and get back to you about our experiences.

External Links