On Wednesday, 23 July 2025 12:19:42 CEST Patryk Bełzak via slurm-users wrote:
> Hi,
>
> we've recentry upgraded our slurm from 24.11.3 to 25.05.1 and it seems that
> since the upgrade the ssh X11 forwaring is broken.
>
> Quick recap -
> * on Monday 14'th I performed slurdbd and slurmctld upgrades - X forwarding
> was still working * on Tuesday 15'th I performed slurmd upgrades - X
> forwarding stopped working
>
> The issue is very hard to determine and it looks like it sits somhere in
> slurm code. You can submit a job with --x11 and it starts corretly.
> Xauthority is created, you have all the magic cookies needed, but when you
> try to start any application, you get error related to permissions I guess,
> see for yourself:
>
> ```
>  me@sand ~ ssh -X -Y ui
> [wcss] me@ui.wcss.pl:~ > srun -p lem-cpu-short -A kdm-staff
> --gres=storage:local:50G -c 12 --mem 12G -t 1:0:0 --x11 --pty /bin/bash
> [wcss] me@r17ch05b01 ~ > xauth list
> r17ch05b01.lem.kdm.wcss.pl/unix:91  MIT-MAGIC-COOKIE-1  d82a2efd
> [wcss] me@r17ch05b01 ~ > xterm
> xterm: Xt error: Can't open display: localhost:91.0
> [wcss] me@r17ch05b01 ~ > date && telnet -4 localhost 6091 || date
> Wed Jul 23 12:02:39 CEST 2025
> Trying 127.0.0.1...
> Connected to localhost.
> Escape character is '^]'.
> Connection closed by foreign host.
> Wed Jul 23 12:02:41 CEST 2025
> ```
>
> As you can see the connection to port is being dropped/killed after a second
> or two. Now, it doesn't really matter which flags for ssh you pick (-X or
> -Y or both). X forwarding is working when you log in as a regular user
> outside of slurm job. Also if I do ssh localhost inside a job, then I can
> perform connection to port assigned to $DISPLAY and it isn't dropped - but
> it doesn't work since $DISPLAY and cookies are being messed up when you
> perform triple jump and one within same host.
>
> Our worker nodes are mostly on el9.5 AlmaLinux. Some are on el8.10 - and
> there acutally you can do some X forwarding but you must use both -X and -Y
> (which wasn't the case before slurm upgrade). TLS is disabled in
> slurm.conf. I am 100% sure that both SSHD and Xorg are properly configured.
>
> Has anyone encountered similiar issue? Or any comment from slurm dev team?
>
> Best regards
> Patryk
> --
> Wroclaw Centre for Networking and Supercomputing


I did create a bug report:

https://support.schedmd.com/show_bug.cgi?id=23190

I got the following response per email:
Currently, this bug is showing as unsupported in our system. Unsupported bugs
are given a very low priority and most times the unsupported bugs are never
reviewed by the support team as their focus is on sites with support
contracts.

If you have a support contract you might rice the priority.


regards
Markus Köberl
--
Markus Koeberl
Graz University of Technology
Signal Processing and Speech Communication Laboratory
E-mail: markus.koeberl@tugraz.at