The default Rocks configuration does not enable rsh commands or login to compute nodes. Instead, Rocks uses ssh as a drop in replacement for rsh. There may be some circumstances where ssh does not have exactly the same semantics of rsh. Further, there may be some users that cannot modify their application to switch from rsh to ssh. If you are one of these users you may wish to enable rsh on your cluster.
Enabling rsh on your cluster has serious security implicatations. While it is true rsh is limited to the private-side network this does not mean it is as secure as ssh.
Enabling rsh is done by setting an attribute. To enable rsh on all compute nodes, execute:
# rocks set appliance attr compute rsh true
To apply this configuration change to the compute nodes, reinstall all your compute nodes.
If you only want to enable rsh on a specific node (e.g., compute-0-0), execute:
# rocks set host attr compute-0-0 rsh true
To apply this configuration change to compute-0-0, reinstall compute-0-0.