[torqueusers] Passwordless_ssh on a diskless cluster

Gelonia L Dent gdent at amnh.org
Mon Apr 28 09:48:29 MDT 2008

Dear All,

I am trying to eliminate using password login between the headnode and
compute nodes on a diskless cluster. I've using the following steps:

On head:
ssh-keygen -t rsa         (didn't enter a pass phrase)
ssh-copy-id -i ~/.ssh/id_rsa.pub nodeN   (for a subset of the nodes

On compute nodes
ssh-keygen -t rsa
ssh-copy-id -i ~/.ssh/id_rsa.pub master

I have three issues:
First, I did this on ten nodes, then something happened and I had to
restart the sshd daemon, now I've lost connection to those ten nodes
completely. I think my authorized_keys file got overwritten when I
restarted ssh. How can I reach these nodes again?
      Error message/       ssh: connect to host node10 port 22: No route
to host

Second, the first time I attempted this (before I broke those 10 nodes) I
neglected to copy the same id_rsa.pub file to all the nodes and was
generating a different one for each node. I've since corrected that step
and am copying the same *.pub file from the head to all the nodes, then
generating a *.pub from each node to the head. This gives me
bi-directional access between each node and the head, but not between
nodes. Do I need passwordless access between nodes for Moab/Torque to work
properly? If so, how can this be accomplished.

Third, today I am attempting again to go through this process. I have 128
nodes. Is there a parameter in the sshd_config  file that is set to use
passwords across the nodes which I may have overlooked. If so, can it be
used to set a 'no password option' permanently between the head and
compute nodes.

Any ideas would be greatly appreciated.


Gelonia Dent, PhD
Manager of Scientific Computing
Invertebrate Zoology
The American Museum of Natural History
(212) 313-7911

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