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Accessing Argonne BG/L
In order to run jobs on Argonne BG/L, you must log onto the Argonne BG/L login servers
(sometimes referred to as front-ends). Access to Argonne BG/L 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 Argonne BG/L login servers is allowed from anywhere on the
Internet. Argonne BG/L compute nodes are only accessible from the front-ends
and the other compute nodes.
To log onto the Argonne BG/L cluster from a unix machine, you would
ssh to the cluster alias bgl.mcs.anl.gov with
the following command:
ssh bgl.mcs.anl.gov
If your username on your local machine is different from your username
on the Argonne BG/L cluster, you will need specify the Argonne BG/L 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 <bgl_username> bgl.mcs.anl.gov
Prepending your username to the hostname is done with the @ symbol:
ssh <bgl_username>@bgl.mcs.anl.gov
This format is particularly useful when copying files to and from Argonne BG/L.
Copying files to and from Argonne BG/L can be accomplished with the
scp command. The format of the scp command is very similar
to the format of using ssh:
scp <localfile> bgl.mcs.anl.gov:<path-to-remotefile>
If you wish to copy an entire directory, use the -r option:
scp -r <localdir> bgl.mcs.anl.gov:<path-to-remotedir>
Once again, if your local username differs from your Argonne BG/L username,
you will need to specify the Argonne BG/L username within the scp command.
The -l option will not work, so you must preprend the username:
scp <localfile> <bgl_username>@bgl.mcs.anl.gov:<path-to-remotefile>
The method used to copy files to and from Argonne BG/L 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 Argonne BG/L network. This
can make copying files from Argonne BG/L 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 Argonne BG/L files using scp on your local
machine:
scp bgl.mcs.anl.gov:<path-to-remotefile> <localfile>
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
Argonne BG/L 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
Argonne BG/L support for help.
The bgl.mcs.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.
Last Updated: 12/5/2006
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