Logging In

To log in to the Laguna login node (also known as the head node), you need to use a secure shell client and a public SSH key. The secure shell client is a small application that enables you to connect to a remote computer via SSH (Secure SHell), a cryptographic network protocol for securely operating network services.

0.0.1 Generate SSH keys

Generating a key pair provides you with two long string of characters: a public and a private key. You can place the public key on any server, and then unlock it by connecting to it with a client that already has the private key. When the two match up, the system unlocks without the need for a password. You can increase security even more by protecting the private key with a passphrase.

Once the keys have been generated, update your public SSH key in your Laguna user portal profile.

0.0.1.1 Create an RSA key pair

The first step is to create the key pair on your personal computer:

$ ssh-keygen -t rsa -b 4096

This command prompts you to designate a location for the keys to be saved:

Enter file in which to save the key (/home/user_id/.ssh/id_rsa):

You can press enter here, saving the file to the default directory (e.g., /home/user_id/.ssh/id_rsa on macOS or Linux or C:\Users\user_id\.ssh\id_rsa on Windows).

Next is the passphrase prompt:

Enter passphrase (empty for no passphrase):

Using a passphrase is optional. A passphrase provides added security, but keep in mind that you have to type it in each time you use the key pair.

The entire key generation process looks something like this:

$ ssh-keygen -t rsa -b 4096
Generating public/private rsa key pair.
Enter file in which to save the key (/home/user_id/.ssh/id_rsa): 
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /home/user_id/.ssh/id_rsa.
Your public key has been saved in /home/user_id/.ssh/id_rsa.pub.
The key fingerprint is:
4a:dd:0a:c6:35:4e:3f:ed:27:38:8c:74:44:4d:93:67 user_id@local
The key's randomart image is:
+--[ RSA 4096]----+
|          .oo.   |
|         .  o.E  |
|        + .  o   |
|     . = = .     |
|      = S = .    |
|     o + = +     |
|      . o + o .  |
|           . o   |
|                 |
+-----------------+

The public key is now located in /home/user_id/.ssh/id_rsa.pub. The private key (identification) is now located in /home/user_id/.ssh/id_rsa.

0.0.1.2 Add public key to user portal

Once the keys are generated, copy the public key.

Mac OS:

cat ~/.ssh/id_rsa.pub | pbcopy

Windows:

cat ~/.ssh/id_rsa.pub

Navigate to the user portal and select your username in the top right corner to display the drop down menu. Select User Profile:

On the next page, delete “None” and paste the public SSH key in the Public SSH Kay (Regional cluster users only) field. Select the Update SSH Key button to the right of the text field when you’re done.

You can now SSH into the login node.

ssh <username>@laguna.carc.usc.edu

ssh <username>@laguna.carc.usc.edu