[slurm-users] slurm-17.11.5 usage of X11

[Philippe Grevet]

Hello,

We have some problem to use native X11 of  the new slurm version (17.11.5) compiled from source on Debain stretch.

Before we use the plugin spank with no problem on an older version of slurm.

I have first this error

"error: X11 forwarding not built in, cannot enable."

After reading different mails,i add

in slurm.conf

PrologFLags=X11

 

and in /etc/ssh/sshd_config (on  head login server of the cluster)

X11UseLocalhost=no

The error change and become

X11 connection rejected because of wrong authentication.

X11Forwarding is working because if i first open a interactive session, and then connect whith ssh -X on the node, the x-application is working fine and displayed on my client computer.

Then I look at .Xauthority file

( first i removed it and recreate a new)

#ssh -X me@cluster

#echo $DISPLAY

cluster:11.0

#xauth list

cluster.ips2.u-psud.fr:11  MIT-MAGIC-COOKIE-1  2809a05f53f693e416682f4befa76a39

#

$ srun    --pty bash --init-file /etc/profile

me@node4:~$ echo $DISPLAY
cluster:11.0
#

#$ xauth list
node4.ips2.u-psud.fr:11  MIT-MAGIC-COOKIE-1  2809a05f53f693e416682f4befa76a39

###the hostname is now the hostname of the node

me@node4:~$ xeyes
X11 connection rejected because of wrong authentication.
Error: Can't open display: cluster:11.0

###But if i add :

#

me@node4:~$ xauth add cluster.ips2.u-psud.fr:11  MIT-MAGIC-COOKIE-1  2809a05f53f693e416682f4befa76a39

#I now can run x-application

Have you an idea of the problem ?

(User login/password authentification of the cluster are done again an Active Directory annuaire with sssd )

 

Philippe GREVET philipp...@ips2.universite-paris-saclay.fr Tel   0169153393        Bureau - 241  Bâtiment -630 http://www.ips2.u-psud.fr/

[John Hanks]

Hi Philippe,

The built-in --x11 support still has some rough edges to it. Due to a timeout issue with getting xauth set up, I've been patching SLURM with these minor changes:

--- src/common/run_command.c_orig 2018-02-06 15:03:10.000000000 -0800

+++ src/common/run_command.c 2018-02-06 15:26:23.525128464 -0800

@@ -198,7 +198,7 @@

        __func__, script_type, max_wait);

  break;

  }

- new_wait = MIN(new_wait, MAX_POLL_WAIT);

+ new_wait = MIN(new_wait, 10000);

  }

  i = poll(&fds, 1, new_wait);

  if (i == 0) {

--- src/common/x11_util.c.orig 2018-01-19 12:51:10.400391579 -0800

+++ src/common/x11_util.c 2018-01-23 08:00:42.080557637 -0800

@@ -146,7 +146,7 @@

  xauth_argv[1] = xstrdup("list");

  xauth_argv[2] = xstrdup(getenv("DISPLAY"));

 

- result = run_command("xauth", XAUTH_PATH, xauth_argv, 100, &status);

+ result = run_command("xauth", XAUTH_PATH, xauth_argv, 10000, &status);

 

  debug2("%s: result from xauth: %s", __func__, result);

 

The longer wait makes it work almost everywhere on our system. However, I still have a small number of users for whom it fails and we still haven't figured out why.

Best,

jbh

 

Philippe GREVET philippe.grevet@ips2.universite-paris-saclay.fr

[Chris Samuel]

On Saturday, 14 April 2018 3:48:56 AM AEST John Hanks wrote:

> The built-in --x11 support still has some rough edges to it. Due to a
> timeout issue with getting xauth set up, I've been patching SLURM with
> these minor changes:

Very interesting John, I've not seen this reported for us (yet - it seems to
work pretty well so far on our systems) but worth keeping in mind for the
future. Thanks for sharing!

--
Chris Samuel : http://www.csamuel.org/ : Melbourne, VIC