Loris,
Your analogy is incorrect, because Slurm doesn't use SSH to launch jobs,
it uses it's own communication protocol, which uses munge for
authentication. Some schedulers used to use ssh to launch jobs, but most
have moved to using their own communications protocol outside of SSH.
It's possible that Slurm used SSH in the early days, too. I wouldn't
know. I've only been using Slurm for the past 5 years.
In those cases, you usually needed host-based SSH so that the scheduler
daemon could launch jobs on the compute nodes. In that situation, you
would be able to ssh from one node to another without per-user ssh keys,
since they'd already be setup on a per-host basis. Perhaps that's what
you are remembering.
Prentice
On 5/25/21 8:09 AM, Loris Bennett wrote:
Hi everyone,
Thanks for all the replies.
I think my main problem is that I expect logging in to a node with a job
to work with pam_slurm_adopt but without any SSH keys. My assumption
was that MUNGE takes care of the authentication, since users' jobs start
on nodes with the need for keys.
Can someone confirm that this expectation is wrong and, if possible, why
the analogy with jobs is incorrect?
I have a vague memory that this used work on our old cluster with an
older version of Slurm, but I could be thinking of a time before we set
up pam_slurm_adopt.
Cheers,
Loris
Brian Andrus <toomuc...@gmail.com> writes:
Oh, you could also use the ssh-agent to mange the keys, then use 'ssh-add
~/.ssh/id_rsa' to type the passphrase once for your whole session (from that
system).
Brian Andrus
On 5/21/2021 5:53 AM, Loris Bennett wrote:
Hi,
We have set up pam_slurm_adopt using the official Slurm documentation
and Ole's information on the subject. It works for a user who has SSH
keys set up, albeit the passphrase is needed:
$ salloc --partition=gpu --gres=gpu:1 --qos=hiprio --ntasks=1
--time=00:30:00 --mem=100
salloc: Granted job allocation 7202461
salloc: Waiting for resource configuration
salloc: Nodes g003 are ready for job
$ ssh g003
Warning: Permanently added 'g003' (ECDSA) to the list of known hosts.
Enter passphrase for key '/home/loris/.ssh/id_rsa':
Last login: Wed May 5 08:50:00 2021 from login.curta.zedat.fu-berlin.de
$ ssh g004
Warning: Permanently added 'g004' (ECDSA) to the list of known hosts.
Enter passphrase for key '/home/loris/.ssh/id_rsa':
Access denied: user loris (uid=182317) has no active jobs on this node.
Access denied by pam_slurm_adopt: you have no active jobs on this node
Authentication failed.
If SSH keys are not set up, then the user is asked for a password:
$ squeue --me
JOBID PARTITION NAME USER ST TIME NODES
NODELIST(REASON)
7201647 main test_job nokeylee R 3:45:24 1 c005
7201646 main test_job nokeylee R 3:46:09 1 c005
$ ssh c005
Warning: Permanently added 'c005' (ECDSA) to the list of known hosts.
nokeylee@c005's password:
My assumption was that a user should be able to log into a node on which
that person has a running job without any further ado, i.e. without the
necessity to set up anything else or to enter any credentials.
Is this assumption correct?
If so, how can I best debug what I have done wrong?
Cheers,
Loris
