Connecting on Mac

Mac computers come with a Secure Shell (SSH) program called Terminal that you use to connect to the HPC using SSH. If you need to use software that uses a GUI, such as Matlab or Maestro, make sure to use the -Y option in the second step below using X11 forwarding.

Note

If you use Mac OS X version 10.8 or higher, and you have XQuartz running in the background to do X11 forwarding, you should execute the following command in Terminal once before connecting:

defaults write org.macosforge.xquartz.X11 enable_iglx -bool true

You should keep XQuartz running in the background. If you close and restart XQuartz, you will need to execute the above command again after restarting. Do not use the Terminal application from within XQuartz to sign in to Discovery. Use the default Terminal program that comes with your Mac (see Step 1 in the procedure below).

Connecting To Cluster On A Mac

  1. Go to Finder > Applications > Utilities, and then double click Terminal.

  2. At the prompt, type ssh <username>@login.discovery.neu.edu, where <username> is your Northeastern username. If you need to use X11 forwarding, type ssh -Y <username>@login.discovery.neu.edu.

  3. Type your Northeastern password and press Enter.

You are now connected to Discovery at a login node.

Passwordless SSH On A Mac

You must set up passwordless ssh to ensure that GUI-based applications launch without issues. Please make sure that your keys are added to the authorized.key file in your ~/.ssh directory. This needs to be done anytime you regenerate your SSH keys. If you are having an issue opening an application that needs X11 forwarding, such as MATLAB or Schrodinger, and you recently regenerated your keys, make sure to add your keys to the authorized.key file.

Note

Ensure you’re on your local computer for steps 1 through 4—type exit to return to your local computer if connected to the cluster.

  1. On a Mac, open the Terminal application and type cd ~/.ssh. This moves you to the ssh folder on your local computer.

  2. Type ssh-keygen -t rsa to generate two files, id_rsa and id_rsa.pub.

  3. Press Enter on all the prompts (do not generate a passphrase).

  4. Type ssh-copy-id -i ~/.ssh/id_rsa.pub <yourusername>@login.discovery.neu.edu to copy id_rsa.pub to your /home/.ssh folder on Discovery. You can enter your NU password if prompted. This copies the token from id_rsa.pub file to the authorized_keys file, which will either be generated or appended if it already exists.

  5. Connect to Discovery via ssh <yourusername>@login.discovery.neu.edu. You should now be connected without having to enter your password.

Now on the cluster,

  1. Type cd ~/.ssh to move to your ssh folder.

  2. Type ssh-keygen -t rsa to generate your key files.

  3. Press Enter on all the prompts (do not generate a passphrase). If prompted to overwrite a file, type Y.

  4. Type cat id_rsa.pub >> authorized_keys. This adds the contents of your public key file to a new line in the ~/.ssh/authorized_keys file.

X11 on Mac OS

From a Mac Terminal log in using the -Y option (ssh -Y <yourusername>@login.discovery.neu.edu).

Tip

If you used the -Y option to enable X11 forwarding on your Mac, you can test to see if it is working by typing xeyes. This will run a small program that makes a pair of eyes appear to follow your cursor.