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When you reinstall the cluster, you reinstall ssh!
This means that ssh on "master" will complain when you try
to connect to these machines that the RSA host key of
the newly installed machine has changed, and you will
be prompted for confirmation before being able to
establish a connection.   This of course
breaks automaticity (noninteractivity).

To get over this problem there is a script <TODO L>host_clean.sh</TODO>
that will clear out the old RSA host key for a machine.  It only
works for one machine at a time and can be invoked as:

	bin/host_clean.sh slave003

  to erase the key for slave003 for example.
 
To clear out all keys at once, simply remove the file $HOME/.ssh/known_hosts.

Then noninteractivity is still broken since ssh will now prompt you
that you are connecting to an unknown host. 

root@master:~# ssh slave003
The authenticity of host 'slave003 (192.168.2.3)' can't be established.
RSA key fingerprint is e6:36:23:2f:45:19:51:b3:0f:33:40:31:74:c5:26:8f.
Are you sure you want to continue connecting (yes/no)?

To fix this, connect once with ssh alone as shown above and answer 'yes'.
After this the RSA host key will be added to $HOME/.ssh/known_hosts and you
won't be prompted again until of course, you reinstall.

This is impractical for 60 some machines.  In that case, use
the scripts 'bin/ssh-no-strict-all.sh' on all hosts (in the <TODO L>hostsup file</TODO>),
with some simple command such as "uptime".

	bin/ssh-no-strict-all.sh uptime

This script employs ssh with the StrictHostKeyChecking option set to no.
Given on the command line to ssh as "ssh -o -o StrictHostKeyChecking=no $host $command".

These operations must be performed before scripts such as rsync.passwords can be run
noninteractively.

Peter