On 02/29/2012 04:51 PM, Martin Siegert wrote:
> On Wed, Feb 29, 2012 at 09:09:27PM +0000, Denver Smith wrote:
>> 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.
> 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).
What has been said for Torque also holds true for SGE - if you compile
Open MPI with the --with-sge switch, passwordless SSH is not needed
since Open MPI will work directly with SGE .
And as much as I agree passwordless SSH keys are not desirable, they can
be difficult to avoid., especially if you use commercial software on
your cluster. MATLAB, for example requires passwordless SSH between
cluster nodes in order to work.