Take the single line out of ~/.ssh/identity.pub, or ~/.ssh/id_dsa.pub, or ~/.ssh/id_rsa.pub, and put it into root's authorized_keys file on all cluster machines. Run this command on each of the cluster machines as root:
ssh -v -l myid exerciser cat /home/myid/.ssh/id_dsa.pub \ >> ~root/.ssh/authorized_keys # with old (version 1) ssh, this would be: ssh -v -l myid exerciser cat /home/myid/.ssh/identity.pub \ >> ~root/.ssh/authorized_keysYou will probably have to provide your password, and possibly say "yes" to some questions about accepting the identity of the test machines. You must also do the corresponding update for the testmonitor machine itself as root:
cat /home/myid/.ssh/identity.pub >> ~root/.ssh/authorized_keysTo test this, try this command from the testmonitor-machine for each of your testmachines, and for the testmonitor-machine itself.
ssh -l root othermachineIf this works, without prompting for a password, you're in business... If not, you need to look at the ssh/openssh documentation and the output from
the -v options above. You may need to enable root logins (PermitRootLogins yes in /etc/ssh/sshd_config).