How to use SSH

SSH standards for Secure Shell. It allows you to connect and work on the HPC remotely via the Internet. It is the primary way that most users interact with RCC resources.

Commonly Accessed Servers

Below are RCC servers that users commonly access:

HPC Submit Nodes

ssh [username]@hpc-login.rcc.fsu.edu

Spear Login Node with X11 forwarding

ssh -X [username]@spear-login.rcc.fsu.edu

Condor Login Node

ssh [username]@condor-login.rcc.fsu.edu

Prerequisites for using SSH

In order to connect to most of our servers, you need to either be on the FSU campus network or connected to the FSU VPN.

You must also have an RCC account. You can create an account or check your account status on our Account Page.

Using SSH in Windows

Windows systems do not have any built-in support for using SSH, so you will have to download a software package to use SSH.

PuTTY is the most popular open source (ie free) SSH client for Windows. To install it, visit the download site, and download the Installer package.

Once installed, find the PuTTy application shortcut in your Start Menu, desktop, or in the Windows 8 start screen. The PuTTy Configuration dialog should appear:

Locate the Host Name input box in the PuTTy Configuration screen. Enter the server name you wish to connect to (e.g. [username]@hpc-submit.rcc.fsu.edu), and click Open. Enter your password when prompted, and press Enter. You are now connected!

Using SSH in Mac or Linux

Both Mac and Linux systems provide a built-in SSH client, so there is no need to install an additional package. Simply locate and run the Terminal app.

Once in the terminal, you can connect to an SSH server by typing the following command:

ssh [username]@[hostname]

For example, to connect to the HPC Login Node, with the username jdoe:

ssh jdoe@submit.hpc.fsu.edu

You will be prompted for a password, and then will be connected to the server:

ssh jdoe@submit.hpc.fsu.edu
Last login: Wed Nov  6 08:41:31 2013 from 144.174.11.12
Welcome to the FSU High Performance Computing Cluster. 

If you have any questions about usage of the cluster or if you need some
assistance, please email support@hpc.fsu.edu.

Information on how to use the job scheduler can be found on the HPC website:
http://www.hpc.fsu.edu/moab

General Access Login Node
[jdoe@submit ~]$ 

Notice the jdoe@submit section of the last line. That indicates that you are now connected to the 'submit' server.

To disconnect from the remote server, simply type exit or close the terminal window.

Using SSH Keys

By default, our SSH servers will prompt you for a password when you attempt to login. As an alternative, you can use PKI (Public Key Authentication) to login to RCC resources. This is particularly useful if you need to use an automated process to connect to our servers.

SSH keys on Linux or Mac

  1. Create a public-key pair: ssh-keygen -t rsa
    • You will be prompted to enter a passphrase. This is optional, but we strongly recommend that you do so.
  2. After running that command, you will have two new files: ~/.ssh/id_rsa and ~/.ssh/id_rsa.pub
    • id_rsa is your private key file. Do not share this with anybody! It is analagous to your password; anybody who has this file can impersonate you.
    • id_rsa.pub is your public key file. You will upload this onto any servers that you wish to automatically login to.
  3. Copy the public key to the server (you will need to enter your password this one time): ssh-copy-id username@server.address
  4. If your computer does not support the ssh-copy-id commmand, run the following commands:
    1. scp ~/.ssh/id_rsa.pub username@server.address
    2. ssh username@server.address (you will need to use your password this time)
    3. Once on the server, copy the key into the appropriate file: mkdir -p ~/.ssh && cat ~/id_rsa.pub > .ssh/authorized_keys && rm ~/id_rsa.pub
  5. Logout and attempt to login to the server again. You should not be prompted for a password!

SSH keys on Windows

To setup SSH keys on Windows with the PuTTy client, refer to the official PuTTy documentation.

Enabling X11 Tunneling (graphical programs over SSH)

SSH, by default, allows you to run remote commands on a server in text mode. You can also use SSH to run graphical programs remotely, such as Matlab.

On Linux and Mac clients, simply include the -X parameter when connecting via SSH:

ssh -X fsuid@spear-login.rcc.fsu.edu

This option will enable remote graphical programs, such as Matlab or VISIT to run over SSH. For example, on the Spear system, after connecting with the -X parameter, you should be able to execute the matlab command and see the Matlab graphical user interface.

Windows users need to perform additional steps, since Windows does not include built-in support for SSH. Penn State Research Computing Center provides an excellent tutorial for setting this up, which uses a free software package called Xming.

A commercial alternative to Xming which works for our systems is MobaXTerm.

Further Reading

If you are new to SSH or Linux, there are a few tutorials on the web which may help you get started: