[slurm-users] slurm 17.11.2 and X11 forwarding on CentOS 7.4

[Marcus Wagner]

Hi folks,

I wonder, if there is anyone here, who has an actual slurm running on
CentOS 7.4 with the (slurm-)native X11 forwarding mechanism.

Is Untrusted X11 Forwarding (-X) needed or does Trusted X11 Forwarding
(-Y) also function?

For some reason, we cannot use ssh -X from a CentOS 7.4 client to a
CentOS 7.4 server. We always get the following message:
Warning: untrusted X11 forwarding setup failed: xauth key data not generated

This does not happen, if we login from a Centos 6.9 client. Really
strange ...


Best
Marcus

--
Marcus Wagner, Dipl.-Inf.

IT Center
Abteilung: Systeme und Betrieb
RWTH Aachen University
Seffenter Weg 23
52074 Aachen
Tel: +49 241 80-24383
Fax: +49 241 80-624383
wag...@itc.rwth-aachen.de
www.itc.rwth-aachen.de

[Marcus Wagner]

Hmm...

I found out some more interesting things:

It does not work, if I do

$> srun --x11 xterm
the error is:
X11 connection rejected because of wrong authentication.
/usr/bin/xterm: Xt error: Can't open display: localhost:77.0
srun: error: linuxbmc0253: task 0: Exited with exit code 1

but the following is functional:
$> salloc srun --x11 xterm
yet I get an "error:
srun: error: Ignoring --x11 option for a job step within an existing
job. Set x11 options at job allocation time.


Ok, so I thought, use --x11 on salloc:
$> salloc --x11 srun xterm
X11 connection rejected because of wrong authentication.
/usr/bin/xterm: Xt error: Can't open display: localhost:51.0
srun: error: linuxbmc0253: task 0: Exited with exit code 1

neither does additionally adding --x11 to srun:
$> salloc --x11 srun --x11 xterm
srun: error: Ignoring --x11 option for a job step within an existing
job. Set x11 options at job allocation time.
X11 connection rejected because of wrong authentication.
/usr/bin/xterm: Xt error: Can't open display: localhost:57.0
srun: error: linuxbmc0253: task 0: Exited with exit code 1


any comments welcome ...


Best
Marcus