[slurm-users] About x11 support

[Marcus Wagner]

Hi Chris,

I really think, it is not that uncommon. But in another way like Tina 
explained.

We HAVE special loginnodes to the cluster, no institute can submit from 
their workstations, they have to login to our loginnodes.
BUT, they can do it not only by logging in per ssh, but also per FastX, 
which provides a full desktop to the user, in our case the user can 
choose between MATE and XFCE.
The DISPLAY variable after login is set e.g. to ":104", since there are 
many users on the nodes. So, to use X11 forwarding with native SLURM, 
the user needs to login to another host with "ssh -X", which is at least 
inconvenient, if not even confusing for the user.

This might be ok, if you have a small group of users, which can be 
trained before they use the cluster. But we have about 40.000 students 
which at least theoretically could use the cluster. We see over one year 
about 2600 different users on the cluster, only 400 or so are constant 
users.

@Mahmood:
Sorry, if you misunderstood me. I did not mean to login to one of the 
computenodes, but slurm does not accept a socket in the DISPLAY 
variable, this is why you have to login somewhere else with X11 
forwarding, or like Tina explained at least to localhost again with X11 
forwarding.


Best
Marcus


On 11/22/2018 12:05 PM, Chris Samuel wrote:
> On Thursday, 22 November 2018 9:24:50 PM AEDT Tina Friedrich wrote:
>
>> I really don't want to start a flaming discussion on this - but I don't
>> think it's an unusual situation.
> Oops sorry, I wasn't intending to imply it wasn't a valid way to do it, it's
> just that across the many organisations I've helped with HPC systems down here
> it's not something I'd come across before.   Even the couple that had common
> authN/authZ configs between user workstations and clusters had the management
> nodes firewalled off so the only access to the batch system was by ssh into
> the login nodes of the cluster.
>
> I think it's good to hear from sites where this is the case because we can
> easily get stuck in our own little bubbles until something comes and trips us
> up like that.
>
> All the best!
> Chris

-- 
Marcus Wagner, Dipl.-Inf.

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