[slurm-users] x11 forwarding not available?

[Tina Friedrich]

Regular ssh forwarding worked just fine with the long hostnames. It's just 
SLURMs version thereof that doesn't. (I think same for DSA/RSA keys etc). 

Tina

On Tuesday, 16 October 2018 09:31:17 BST Dave Botsch wrote:
> That's not the issue, here (though I have experienced that before).
> Regular ssh forwarding works fine.
> 
> On Tue, Oct 16, 2018 at 09:47:21AM +0100, Tina Friedrich wrote:
> > I had an issue getting x11 forwarding via SLURM (srun/sbatch) to work; ssh
> > worked fine. Tracked it down to the host name setting on the nodes; as per
> > RedHat/CentOS default, the hostname was set to the fully qualified. Turns
> > out SLURMs X11 forwarding doesn't work with that; setting the hostnames
> > to the short hostname made it all magically work.
> > 
> > Tina
> > 
> > On Tuesday, 16 October 2018 09:29:01 BST Olivier Sallou wrote:
> > > On 10/16/2018 01:07 AM, Dave Botsch wrote:
> > > > Hi.
> > > > 
> > > > X11 forwarding is enabled and works for normal ssh.
> > > 
> > > I faced same issue, with ssh x11 working as expected on compute nodes,
> > > but not with slurm -x11.
> > > 
> > > I patched slurm locally to make it work.
> > > 
> > > what you can try to see if it is the same issue:
> > > 
> > > 
> > > srun -n1 --pty --x11 --pty bash
> > > 
> > > 
> > > # xterm
> > > // you should have an authorization failure error
> > > 
> > > // on connected node
> > > # xauth list
> > > 
> > > you will have a list of MAGIC COOKIE like
> > > 
> > > myslurmmaster/unix:10  MIT-MAGIC-COOKIE-1  YYYYYY
> > > myslurmnode/unix:52  MIT-MAGIC-COOKIE-1  XXXXXX
> > > 
> > > # echo $DISPLAY
> > > localhost:52.0
> > > 
> > > 
> > > To make it work manually I did (of course adapting node names and
> > > display port number):
> > > 
> > > xauth remove myslurmnode/unix:52
> > > xauth add localhost:52.0
> > > 
> > > then xterm (for example) worked.
> > > 
> > > If this is the same problem, slurm can be easilly patched to work (can
> > > give you how)
> > > 
> > > Olivier
> > > 
> > > > Thanks.
> > > > 
> > > > On Mon, Oct 15, 2018 at 09:55:59PM +0000, Rhian Resnick wrote:
> > > >> Double check /etc/ssh/sshd_config allows X11 forwarding on the node
> > > >> as it
> > > >> is disable by default. (I think)
> > > >> 
> > > >> 
> > > >> X11Forwarding yes
> > > >> 
> > > >> 
> > > >> 
> > > >> 
> > > >> Rhian Resnick
> > > >> 
> > > >> Associate Director Research Computing
> > > >> 
> > > >> Enterprise Systems
> > > >> 
> > > >> Office of Information Technology
> > > >> 
> > > >> 
> > > >> Florida Atlantic University
> > > >> 
> > > >> 777 Glades Road, CM22, Rm 173B
> > > >> 
> > > >> Boca Raton, FL 33431
> > > >> 
> > > >> Phone 561.297.2647
> > > >> 
> > > >> Fax 561.297.0222
> > > >> 
> > > >>  [image] <https://hpc.fau.edu/wp-content/uploads/2015/01/image.jpg>
> > > >> 
> > > >> ________________________________
> > > >> From: slurm-users <slurm-users-bounces at lists.schedmd.com> on behalf
> > > >> of
> > > >> Dave Botsch <botsch at cnf.cornell.edu> Sent: Monday, October 15, 2018
> > > >> 5:51
> > > >> PM
> > > >> To: slurm-users at lists.schedmd.com
> > > >> Subject: [slurm-users] x11 forwarding not available?
> > > >> 
> > > >> 
> > > >> 
> > > >> Wanted to test X11 forwarding. X11 forwarding works as a normal user
> > > >> just ssh'ing to a node and running xterm/etc.
> > > >> 
> > > >> With srun, however:
> > > >> 
> > > >> srun -n1 --pty --x11 xterm
> > > >> srun: error: Unable to allocate resources: X11 forwarding not
> > > >> available
> > > >> 
> > > >> So, what am I missing?
> > > >> 
> > > >> Thanks.
> > > >> 
> > > >> PS
> > > >> 
> > > >> srun --version
> > > >> slurm 17.11.7
> > > >> 
> > > >> rpm -qa |grep slurm
> > > >> ohpc-slurm-server-1.3.5-8.1.x86_64
> > > >> ...
> > > >> 
> > > >> 
> > > >> --
> > > >> ********************************
> > > >> David William Botsch
> > > >> Programmer/Analyst
> > > >> @CNFComputing
> > > >> botsch at cnf.cornell.edu
> > > >> ********************************
> > > >> --
> > > >> ********************************
> > > >> David William Botsch
> > > >> Programmer/Analyst
> > > >> @CNFComputing
> > > >> botsch at cnf.cornell.edu
> > > >> ********************************


-- 
Tina Friedrich, Snr HPC Systems Administrator, Advanced Research Computing
Research Computing and Support Services, Academic IT 
IT Services, University of Oxford 
http://www.arc.ox.ac.uk