SSH (Secure shell)
In this article, step-by-step, we review the process "SSH"ing to RCC's clusters so you know what is happening.
Connecting to RCC clusters through SSH
There are countless 3rd party SSH clients for Windows, Mac, Linux (all flavors), Android, Chromebook, etc. SSH client means an application installed on your computer/phone that can connect your computer (client) to RCC clusters (host) through SSH protocol. Microsft Windows, Apple Mac Computers, and all flavors of Linux come with a preloaded SSH (native) SSH client. Here, we focus on connecting to RCC clusters using these native clients if you are a pro user, consider using other 3rd party, more robust SSH clients (e.g. iTerm2, Termius, etc.)
Apple Macintosh (Mac)
Macintosh machines, through the "terminal," can access the system's native SSH client app. Click on "launchpad," then search and open the "terminal" app.
Microsft Windows (10 and 11) Through the "Windows PowerShell," Windows machines can access the system's native SSH client app. Click on the "start" menu, then search and open the "Windows PowerShell" app.
Windows users running a version older than Windows 10’s April 2018 release will have to download a 3rd party SSH client to connect via SSH. We recommend a free version of Termius SSH client.
Now that we have "terminal" or "PowerShell" open. We can SSH to RCC clusters.
The general format of the command to connect to an SSH host is this:
Here, instead of
username, type in your
hostname, depending on the cluster you need to connect, use one of the following SSH host addresses:
SSH host addresses
|Host name||SSH host address|
|Cluster's host name||SSH host address|
Note: For the family of
MidwayR clusters, please check the MidwayR user guide.
For example, to SSH to Midway3, we type in
ssh email@example.com and then press
enter on Windows or
return on Apple keyboards.
If this is your first time signing into a particular RCC cluster using your computer, the SSH client will ask,
Are you sure you want to continue connecting?. Type
yes and press the 'enter' button on your keyboard.
Then, we get a prompt to enter our CNetID
password. Note, as you type in your password, no character or other symbol will appear, but it is alright; type in your password and press
enter on Windows or
return on Apple keyboards.
Then, the Duo's multi-factor authentication (MFA) prompt asks a few questions.
After Duo's multi-factor authentication (MFA), you land on one of the many RCC's login nodes.
To read more about options (arguments) you could add to your SSH command, check this page.
Login nodes are the "foyer" of the RCC's clusters. They are connected to the internet and enable you to transfer data to and from the system. They are not designed to carry out computing processes, and you should NOT run your scripts on login nodes. To connect to compute nodes to run computationally intensive programs, there is one more step you need to go through.
The login nodes are NOT for computationally intensive work.
Login nodes have a small storage space for users to store a very small volume of data required for back-end processes such as authentication and other system-related processes upon logging in. Login nodes are not a storage space to save and install our packages.
In compliance with the University of Chicago security guidelines, 2FA is required with limited exceptions. If you believe you have a justifiable need for SSH key pairs (only PIs), please contact our helpdesk and describe your situation. Once your request is received, the RCC security team will review it, and we will follow up with you as soon as possible.
To submit (send) jobs (scripts to process) to compute nodes or log into compute nodes directly, check this page.
Storage nodes generally store all files and folders under users' home, scratch, and PI's group project directories. To learn more about how storage nodes are interconnected to compute nodes and across RCC clusters (Midway2, 3, Beagle, DaLi, etc.), check this page.
SCP - secure copy protocol
To copy files and folders from your personal computer (client) to RCC clusters (host) through SSH protocol, we use the following command, known as
SCP (secure copy protocol.)
Terminal (Macintosh) or
Windows Powershell (Windows)
scp <sourceFile> <CNetID>@<hostAddress>:<targetPath>
Example 1-a: Copying a single file from Jane's personal computer (client) to Dr. Pepper's
scp test.txt firstname.lastname@example.org:/project/drpepper/users/jdoe/
Example 1-b: Copying a single file from Jane's personal computer (client) to her
scp test.txt email@example.com:/home/jdoe/Documents/
Example 2-a: Copying a directory (collection of files) from Jane's personal computer (client) to Dr. John's
scp tests -r firstname.lastname@example.org:/project/drpepper/users/jdoe/
Example 2-b: Copying a directory (collection of files) from Jane's personal computer (client) to her
scp tests -r email@example.com:/home/jdoe/Documents/
enter on your keyboard, the rest is the same as logging into RCC clusters through SSH.
SFTP - SSH file transfer protocol
SFTP is another SSH-based file transfer protocol that provides access, transfer, and management over any reliable data stream. RCC clusters support SFTP, and we strongly recommend this protocol for transferring data to/from RCC clusters. Termius SSH client, also supports SFTP.