I built Beuwolf cluster using OpenMPI reading the following link.
I can do ssh to my slave nodes without the slave mpiuser's password before mounting my slaves.
But when I mount my slaves and do ssh, the slaves ask again their passwords.
Master and slaves' ssh directory and authorized_keys have permission 700, 600 respectively and
 they owned only by owner mpiuser through chown.RSA has no passphrase.

Please help me on this matter.