[slurm-users] salloc with bash scripts problem

[Renfro, Michael]

Not sure what the reasons behind “have to manually ssh to a node”, but salloc and srun can be used to allocate resources and run commands on the allocated resources:

Before allocation, regular commands run locally, and no Slurm-related variables are present:

=====

[renfro at login ~]$ hostname
login
[renfro at login ~]$ echo $SLURM_TASKS_PER_NODE


=====

After allocation, regular commands still run locally, Slurm-related variables are present, and srun runs commands on the allocated node (my prompt change inside a job is a local thing, not done by default):

=====

[renfro at login ~]$ salloc
salloc: Granted job allocation 147867
[renfro at login(job 147867) ~]$ hostname
login
[renfro at login(job 147867) ~]$ echo $SLURM_TASKS_PER_NODE
1
[renfro at login(job 147867) ~]$ srun hostname
node004
[renfro at login(job 147867) ~]$ exit
exit
salloc: Relinquishing job allocation 147867
[renfro at login ~]$

=====

Lots of people get interactive shells on a reserved node with some variant of ‘srun --pty $SHELL -I’, which doesn’t require explicitly running salloc or ssh, so what are you trying to accomplish in the end?

-- 
Mike Renfro, PhD / HPC Systems Administrator, Information Technology Services
931 372-3601     / Tennessee Tech University

> On Jan 2, 2019, at 9:24 AM, Mahmood Naderan <mahmood.nt at gmail.com> wrote:
> 
> I want to know if there any any way to push the node selection part on slurm and not a manual thing that is done by user.
> Currently, I have to manually ssh to a node and try to "allocate resources" using salloc. 
> 
> 
> Regards,
> Mahmood
> 
> On Wed, Jan 2, 2019 at 5:54 PM Henkel, Andreas <henkel at uni-mainz.de> wrote:
> Hi,
> As far as I understand salloc is used to make allocations but  initiate a shell (whatever the sallocdefaultcommand specifies) on the node you called salloc. If you’re looking for an interactive session you‘ll probably have to use srun --pty xterm . This will allocate the resources AND initiate a shell on one of the allocated nodes. 
> Best
> Andreas 
> 
> Am 02.01.2019 um 14:43 schrieb Mahmood Naderan <mahmood.nt at gmail.com>:
> 
>> Chris,
>> Can you explain why I can not get a prompt on a specific node while I have passed the node name to salloc?
>> 
>> [mahmood at rocks7 ~]$ salloc
>> salloc: Granted job allocation 268
>> [mahmood at rocks7 ~]$ exit
>> exit
>> salloc: Relinquishing job allocation 268
>> [mahmood at rocks7 ~]$ salloc --nodelist=compute-0-2
>> salloc: Granted job allocation 269
>> [mahmood at rocks7 ~]$ exit
>> exit
>> salloc: Relinquishing job allocation 269
>> [mahmood at rocks7 ~]$ grep SallocDefaultCommand /etc/slurm/slurm.conf
>> #SallocDefaultCommand = "xterm"
>> [mahmood at rocks7 ~]$
>> 
>> 
>> 
>> As you can see the default SallocDefaultCommand is commented. So, I expected to override the default command.
>> 
>> 
>> Regards,
>> Mahmood
>> 
>> 
>> 
>> 
>> On Sun, Dec 30, 2018 at 9:11 PM Mahmood Naderan <mahmood.nt at gmail.com> wrote:
>> So, isn't possible to override that "default"? I mean the target node. In the faq page it is possible to change the default command for salloc, but I didn't see your confirmation.
>> 
>> 
>> I really have difficults with interactive jobs that use x11 or binary files or bash scripts. For some of them, srun doesn't work while salloc works. On the other hand with srun I can choose a target nide while I can't do that with salloc.
>> 
>> Has anybody faced such issues?
>> 
>> On Sun, Dec 30, 2018, 20:15 Chris Samuel <chris at csamuel.org> wrote:
>> On 30/12/18 7:16 am, Mahmood Naderan wrote:
>> 
>> > Right...
>> > I also tried
>> > 
>> > [mahmood at rocks7 ~]$ salloc --nodelist=compute-0-2 -n 1 -c 1 --mem=4G -p 
>> > RUBY -A y4
>> > salloc: Granted job allocation 199
>> > [mahmood at rocks7 ~]$ $
>> > 
>> > I expected to see the compute-0-2 prompt. Is that normal?
>> 
>> By default salloc gives you a shell on the same node as you ran it on, 
>> with a job allocation that you can access by srun.
>> 
>> You can read more about interactive shells here:
>> 
>> https://slurm.schedmd.com/faq.html#prompt
>> 
>> All the best,
>> Chris
>> -- 
>>   Chris Samuel  :  http://www.csamuel.org/  :  Melbourne, VIC
>>