Thanks, for some reason I edited the /etc/pam.d/sshd via ansible but that
locked all users to the cluster.  That same file works on a different
cluster where the files are pushed via puppet but with ansible it looks
like it is locking all users to the cluster. See below config file sshd:

auth       required     pam_sepermit.so
auth       substack     password-auth
auth       include      postlogin
# Used with polkit to reauthorize users in remote sessions
-auth      optional     pam_reauthorize.so prepare
account    required     pam_nologin.so
##SLURM
account sufficient pam_slurm_adopt.so  action_no_jobs=deny
action_unknown=newest action_adopt_failure=deny action_generic_failure=deny
account    sufficient   pam_access.so
##END SLURM
password   include      password-auth
# pam_selinux.so close should be the first session rule
session    required     pam_selinux.so close
session    required     pam_loginuid.so
# pam_selinux.so open should only be followed by sessions to be executed in
the user context
session    required     pam_selinux.so open env_params
session    required     pam_namespace.so
session    optional     pam_keyinit.so force revoke
session    include      password-auth
session    include      postlogin
# Used with polkit to reauthorize users in remote sessions
-session   optional     pam_reauthorize.so prepare



*Fritz Ratnasamy*Data Scientist
Information Technology




On Wed, Jun 11, 2025 at 8:29 PM Kevin Buckley via slurm-users <
slurm-users@lists.schedmd.com> wrote:

> On 2025/06/11 12:46, Ratnasamy, Fritz via slurm-users wrote:
> >
> > We wanted to block users from ssh to a node where there are no jobs
> > running however it looks like users are able to do so. We have installed
> > the slurm_pam_adopt_module and set up the slurm.conf accordingly (the
> same
> > way we did on our first cluster where the pam module denies ssh access
> > correctly).
>
> We saw a similar issue whereby the way that we had PAM setup, meant
> that, and here I quote from SchedMD's Daniel Armengod:
>
> ----8<--------8<--------8<--------8<--------8<--------8<--------8<----
> This is almost certainly caused by the fact that SSH's
> `keyboard-interactive`
> (not to be confused with `password`) AuthMethod forks a short-lived child
> process that is involved in the authentication logic. Slurm's
> pam_slurm_adopt
> module latches on to that process (which is the wrong one, of course) and
> things break in interesting ways from there.
>
> SSH authmethods `publickey` and `password` do not exhibit this behaviour
> as SSH
> does not fork a child process to offload the authentication
> challenge-response
> dialogue to.
>
> ...
>
> The key bit here is that in your last test you're forcing
> `PreferredAuthentications=password`, which isn't actually the
> `keyboard-interactive` AuthMethod that got picked before.
> They work differently under the hood, even if as far as the
> user is concerned, both methods just ask for a password.
>
> ...
>
> In summary: try disabling the `keyboard-interactive` authentication method
> in
> your compute nodes. pam_slurm_adopt should work correctly now.
> ----8<--------8<--------8<--------8<--------8<--------8<--------8<----
>
> Maybe that's also your issue.
>
>
> Daniel did say that SchedMD were going to update their documentation
> to make that distinction, and it's effect, more explciit, so I would
> expect it to be in the mainstream docs by now.
>
> HTH
>
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