StarCluster’s sshmaster, sshnode, and sshinstance commands now support executing remote commands on a cluster node without logging in interactively. This is especially useful for users looking to script these commands. To do so simply pass the command you wish to run remotely as an additional quoted argument to any of the sshmaster, sshnode, and sshinstance commands.
For example, to check which hosts are listed in the master node’s /etc/hosts file:
$ starcluster sshmaster mycluster 'cat /etc/hosts'
StarCluster - (http://star.mit.edu/cluster)
Software Tools for Academics and Researchers (STAR)
Please submit bug reports to starcluster@mit.edu
10.10.10.1 master
10.10.10.2 node001
10.10.10.3 node002
or to quickly check the files in a given directory on node001:
$ starcluster sshnode mycluster node001 'ls -l /data'
StarCluster - (http://star.mit.edu/cluster)
Software Tools for Academics and Researchers (STAR)
Please submit bug reports to starcluster@mit.edu
drwxr-xr-x 4 root root 4096 Nov 5 00:06 data-2011
drwxr-xr-x 2 root root 4096 Nov 4 14:21 data-2010
drwxr-xr-x 2 root root 4096 Nov 4 14:23 data-2009
drwxr-xr-x 4 root root 4096 Oct 17 13:42 data-2008
Any command you can run while logged into a cluster interactively can be executed remotely from your local command line simply by quoting the remote command and passing it as an additional argument to any of the sshmaster, sshnode, and sshinstance commands as in the above examples.
If the remote command is successful the exit code of either the sshmaster, sshnode, or sshinstance command will be 0:
$ starcluster sshmaster mycluster 'uptime'
StarCluster - (http://star.mit.edu/cluster)
Software Tools for Academics and Researchers (STAR)
Please submit bug reports to starcluster@mit.edu
00:58:12 up 1 days, 9:49, 2 users, load average: 0.02, 0.06, 0.12
$ echo $?
0
Otherwise, the exit code will be identical to the remote command’s non-zero exit code:
$ starcluster sshmaster mycluster 'uptimes2'
StarCluster - (http://star.mit.edu/cluster)
Software Tools for Academics and Researchers (STAR)
Please submit bug reports to starcluster@mit.edu
command not found: uptimes2
!!! ERROR - command 'uptimes2' failed with status 127
$ echo $?
127
This allows you to use the sshmaster, sshnode, and sshinstance commands in scripts and check whether or not the remote command finished successfully.
If you have OpenSSH installed and an X server you can enable X11 forwarding over SSH using the --forward-x11 (-X) option. This allows you to run graphical applications on the cluster and display them on your local computer. For example, to run xterm on the master node of mycluster:
$ starcluster sshmaster -X mycluster xterm
The sshnode command also supports the -X option:
$ starcluster sshnode -X mycluster node001 xterm