Using onnode as non-root ssh user

[Steve French]

I noticed that onnode can be very useful for executing a command on
all nodes in a cluster, but relies on ssh and in particular connecting
as root.  Unfortunately the user root may be disabled in some
configurations.  Is there a way to get onnode to ssh as an admin user
other than root? is there a way to pass ssh parms to onnode
automatically (password or key file etc.)?

-- 
Thanks,

Steve