Accessing Fusion

In order to run jobs on Fusion, you must log onto the Fusion login servers
(sometimes referred to as front-ends). Access to Fusion using cleartext
passwords (password that are not encrypted) is not allowed. Software
that uses the Secure Shell (SSH) protocol can be used to connect to
the cluster for interactive sessions.

Access to the Fusion login servers is allowed from anywhere on the
Internet. Fusion compute nodes are only accessible from the front-ends
and the other compute nodes.

To log onto the Fusion cluster from a unix machine, you would
ssh to the cluster alias fusion.lcrc.anl.gov with
the following command:

 
ssh fusion.lcrc.anl.gov 

If your username on your local machine is different from your username on the Fusion cluster, you will need specify the Fusion username within the ssh command. This can be done two ways, by using the -l option or by prepending your username to the hostname.

Using the -l option:

 
ssh -l <fusion_username> fusion.lcrc.anl.gov 

Prepending your username to the hostname is done with the @ symbol:

 
ssh <fusion_username>@fusion.lcrc.anl.gov 

This format is particularly useful when copying files to and from Fusion.

Copying files to and from Fusion can be accomplished with the scp command. The format of the scp command is very similar to the format of using ssh:

 
scp <localfile> fusion.lcrc.anl.gov:<path-to-remotefile> 

If you wish to copy an entire directory, use the -r option:

 
scp -r <localdir> fusion.lcrc.anl.gov:<path-to-remotedir> 

Once again, if your local username differs from your Fusion username, you will need to specify the Fusion username within the scp command. The -l option will not work, so you must preprend the username:

 
scp <localfile> <fusion_username>@fusion.lcrc.anl.gov:<path-to-remotefile> 

The method used to copy files to and from Fusion may need to take into account any firewalls between your local machine and the cluster. It is possible that there is a firewall that will prevent access to your local machine from the Fusion network. This can make copying files from Fusion to your local machine seem difficult. If you are logged onto one of the front-ends and you are unable to scp files to your local machine using the standard scp format, try pulling the Fusion files using scp on your local machine:

 
scp fusion.lcrc.anl.gov:<path-to-remotefile> <localfile&gt 

Notice that you are simply swapping the local and remote filenames. The prepending of the username and use of the -r option will work with this format as well.

Once you have connected, you will be prompted for your Fusion password. "Accessed Denied" error messages at login usually mean there is a password or username problem. If you are experiencing this problem, use the -v option to ssh (or scp) to get diagnostic output and send that output, along with your username on both systems to Fusion support for help.

The fusion.lcrc.anl.gov name refers to all currently available user login hosts. Users are placed onto the real hosts in round-robin fashion, as a result you may end up on a different host from one login to the next. Because the real hosts may change without notice, we suggest that you use the alias and not the real hostnames to log onto the cluster.

For more information on using ssh and how to obtain a version for your local machine, please read the MCS Offsite Access document. This document also contains information on why ssh is necessary and pointers to other useful sources of information on ssh and scp.