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Subject: Re: [OMPI users] ssh between nodes
From: Martin Siegert (siegert_at_[hidden])
Date: 2012-02-29 16:51:19


On Wed, Feb 29, 2012 at 09:09:27PM +0000, Denver Smith wrote:
> Hello,
> On my cluster running moab and torque, I cannot ssh without a password
> between compute nodes. I can however request multiple node jobs fine. I
> was wondering if passwordless ssh keys need to be set up between
> compute nodes in order for mpi applications to run correctly.
> Thanks

No. passwordless ssh keys are not needed. In fact, I strong advise
against using those (teaching users how to generate passwordless
ssh keys creates security problems: they start using those not just
for connecting to compute nodes). There are several alternatives:

1) use openmpi's hooks into torque (use the --with-tm configure option);
2) use ssh hostbased authentication (and set IgnoreUserKnownHosts to yes);
3) use rsh (works if your cluster is sufficiently small).

I prefer any of these (in decreasing order) over passwordless ssh keys.


Martin Siegert
Simon Fraser University
Burnaby, British Columbia