[slurm-users] Slurm 19.05 X11-forwarding

Wed Feb 26 09:52:31 UTC 2020

Hi, 

Thank you for your quick replies.
Please bear with me as I am a newbie regarding Slurm and Linux.
My hostname is not a FQDN and I´m running Slurm on a local node (slurmctld and slurmuser are the same) just to verify that the X11-forwarding is working (amongst other things).
The output of "xauth list" is as follows:
"
parlun-E6540/unix:  MIT-MAGIC-COOKIE-1  bcf263421d143e6ba3297dfe926c68b8
#ffff#7061726c756e2d4536353430#:  MIT-MAGIC-COOKIE-1  bcf263421d143e6ba3297dfe926c68b8
"
I seem to be missing any ":0", i.e. to wich display or Xserver my user (parlun-E6540) uses?
I´ve tried adding the user "slurm", who is designated slurmuser, via "xhost +SI:localuser:slurm" but I still get the error stating that the magic cookie could not be retrieved.

You are correct, X11Parameters only holds one option "home_xauthority".
Does this setting automatically search in the "/home/slurm"-dir for the Xauthority-file? (Given that the slurmuser is "slurm").
Trying to locate the storage where xauthoriy is present, I do not find it my home-dir instead it is in some other OS-dir.

Searching for additional help I came across a debian package (xvfb) for virtual framebuffers. i.e. video/GUI is sent to a virtual buffer instead of a physical display. Anyone tried that?
I haven´t not yet installed it, but is curious if that´s a way to go.

Best regards,
Pär Lundö

-----Original Message-----
From: slurm-users <slurm-users-bounces at lists.schedmd.com> On Behalf Of Ryan Novosielski
Sent: den 25 februari 2020 21:23
To: slurm-users at lists.schedmd.com
Subject: Re: [slurm-users] Slurm 19.05 X11-forwarding

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Hash: SHA1

I seem to remember there being a config option to specify rewriting the hostname as well. I thought it was part of X11Parameters, but I only see one option there:

https://slurm.schedmd.com/archive/slurm-19.05-latest/slurm.conf.html

On 2/25/20 10:55 AM, Tina Friedrich wrote:
> I remember having issues when I set up X forwarding that had to do 
> with how the host names were set on the nodes. I had them set (CentOS 
> default) to the fully qualified hostname, and that didn't work - with 
> an error message very similar to what you're getting, if memory serves 
> right. 'Fixed' it by setting the hostnames on all my cluster nodes to 
> the short version.
>
> What does 'xauth list' give you on your nodes (and the machine you're 
> coming from)?
>
> This is/was SLURM 18.08 though, not sure if that makes a difference.
>
> Tina
>
> On 25/02/2020 04:55, Pär Lundö wrote:
>> Hi,
>>
>> Thank you for your reply Patrick. I´ve tried that but I still get the 
>> error stating that the magic cookie could not be retrieved.
>> Reading Tim´s answer, this bug should have been fixed in a release 
>> following 18.08, but I´m using 19.05 thus it should have been taken 
>> care of?
>>
>> Best regards, Pär Lundö
>>
>> -----Original Message----- From: slurm-users 
>> <slurm-users-bounces at lists.schedmd.com> On Behalf Of Patrick Goetz 
>> Sent: den 24 februari 2020 21:38 To:
>> slurm-users at lists.schedmd.com Subject: Re: [slurm-users] Slurm
>> 19.05 X11-forwarding
>>
>> This bug report appears to address the issue you're seeing:
>>
>> https://bugs.schedmd.com/show_bug.cgi?id=5868
>>
>>
>>
>> On 2/24/20 4:46 AM, Pär Lundö wrote:
>>> Dear all,
>>>
>>> I started testing and evaluating Slurm roughly a year ago and used 
>>> it succesfully with MPI-programs. I have now identified that I need 
>>> to use X-forwarding in order to make use of an application needed to 
>>> run a GUI. However I seem not to be able to use the "X11Forwarding" 
>>> in Slurm.conf with any sucess. A simple test with srun as "srun - 
>>> -x11 <script-to-start>", yields an error stating: "srun: error: 
>>> x11_get_xauth: Could not retrieve magic cookie. Cannot use X11 
>>> forwarding." I'm guessing that there some additional setting I'm 
>>> missing out on.
>>> Searching through documentation does not reveal anything 
>>> extraordinary to be performed with the X11-forwarding. I have 
>>> searched bug-reports and found similiar problems but fixes have been 
>>> implemented in Slurm-versions prior to the one I am using.
>>> In addition users have been reporting that the implementation made 
>>> by Slurm, now have fixed their issues. I have used the 
>>> "export=DISPLAY, HOME" as an additional argument for srun but 
>>> without any progress. Anyone with similiar problem who can aid or 
>>> advice me on howto use the X11Forward feature? Any help is much 
>>> appreciated.
>>>
>>> I am running Slurm 19.05 and Ubuntu 18.10.
>>>
>>> Best regards, Pär Lundö
>>>
>>> This message is from an external sender. Learn more about why this 
>>> matters.
>>> <https://ut.service-now.com/sp?id=kb_article&number=KB0011401>
>>>
>>>
>>

- --
 ____
 || \\UTGERS,     |----------------------*O*------------------------
 ||_// the State  |    Ryan Novosielski - novosirj at rutgers.edu
 || \\ University | Sr. Technologist - 973/972.0922 ~*~ RBHS Campus
 ||  \\    of NJ  | Office of Advanced Res. Comp. - MSB C630, Newark
      `'
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