Connect & Log In

Help Desk

Updated: 03/28/2019

Users log into ALCF resources via ssh.

ssh -l <username>

Resources that are accessible via ssh are,, and

Below is an example of the login steps (via ssh command) to the BG/Q Mira system:

$ ssh
                           Notice to Users

This is a Federal computer system and is the property of the United States
Government. It is for authorized use only. Users (authorized or unauthorized)
have no explicit or implicit expectation of privacy.

Any or all uses of this system and all files on this system may be intercepted,
monitored, recorded, copied, audited, inspected, and disclosed to authorized
site, Department of Energy, and law enforcement personnel, as well as
authorized officials of other agencies, both domestic and foreign. By using
this system, the user consents to such interception, monitoring, recording,
copying, auditing, inspection, and disclosure at the discretion of authorized
site or Department of Energy personnel.

Unauthorized or improper use of this system may result in administrative
disciplinary action and civil and criminal penalties. By continuing to use
this system you indicate your awareness of and consent to these terms and
conditions of use. LOG OFF IMMEDIATELY if you do not agree to the conditions
stated in this warning.


Last login: Fri Mar 22 15:15:48 2013 from xxx.yyy.zzz
[USER@miralac1 ~]$ 

If you are experiencing issues with the Mobile or Physical token password entry, consult the token troubleshooting guide ( If you are unable to connect at all (no prompt), please e-mail support and include the IP address you are connecting from.  (One way to determine this is via )

Additional Information About the Login Nodes

The login nodes, also known as the front end nodes, are the nodes where users gain access through the ssh command to the ALCF resources. These nodes enable interactive activities such as editing files and compiling. The compute nodes are not directly accessible to the user; however when the user code is submitted using the qsub command, it is executed in the compute nodes.

It is important to note that the hardware and operating systems of the login and compute nodes are different.

What this means:

  • Code compiled for the hardware and operating system combination of the compute node will not execute on the login node.
  • Code compiled for the login nodes will not run on the compute nodes.
  • By default, code compiled on the login nodes is targeted for the hardware and operating system combination of the compute nodes, which means it will not run on the login node.

This is known as cross compiling.