[slurm-users] ssh-keys on compute nodes?

[Reuti]

Hi,

Am 08.06.2020 um 17:16 schrieb Durai Arasan:

> we are setting up a slurm cluster and are at the stage of adding ssh keys of the users to the nodes.
> 
> I thought it would be sufficient to add the ssh keys of the users to only the designated login nodes. But I heard that it is also necessary to add them to the compute nodes as well for slurm to be able to submit jobs of the users successfully. Apparently this is true especially for MPI jobs.
> 
> So is it true that ssh keys of the users must be added to the ~/.ssh/authorized_keys of *all* nodes and not just the login nodes?

Instead of doing this for each and every user in the cluster, you can also implement hostbased authentication. I put some notes here:

https://arc.liv.ac.uk/SGE/howto/hostbased-ssh.html

Note: inside the cluster each node is a source and/or target machine depending the parallel library, hence both steps must be done. But often the nodes are having an identical image on all nodes anyway. Sure, the login node is a solely a source machine.

Note: I found that with an update of the SSH package the changed permissions bits for /usr/lib64/ssh/ssh-keysign might also get reset, if it's not working after an `rpm -U ssh`, check this flag.

-- Reuti