[slurm-users] Defining an empty partition

[Steve Brasier]

This is reviving a very old thread but for me at least it is still the top
2 hits in google for "define empty slurm partition" so it might help
someone:

The solution here (of defining NodeName=nonesuch) is a bit of red-herring.
I don't know why I never tried this at the time but you can do:

PartitionName=whatever ... Nodes=""

which seems like it is probably what the docs mean
<https://slurm.schedmd.com/slurm.conf.html#OPT_Nodes_1> when they say:

> A blank list of nodes (i.e. "Nodes= ") can be used if one wants a
partition to exist, but have no resources

i.e. the quote position has just got typoed.

Steve

http://stackhpc.com/
Please note I work Tuesday to Friday.


On Fri, 18 Dec 2020 at 13:17, Steve Brasier <steveb at stackhpc.com> wrote:

> Thank you Tina, I hadn't realised that would show as "n/a" not "down" in
> that case (which IMO would have been confusing). For anyone else hitting
> this I think the minimum you can do is something like:
>
> PartitionName=compute Default=YES <options> State=UP Nodes=nosuch
> NodeName=nosuch
>
> The documented approach would have been easier in my case given
> the constraints of the template logic generating this but at least it's a
> workaround.
>
> thanks
> Steve
>
> http://stackhpc.com/
> Please note I work Tuesday to Friday.
>
> On 18/12/2020 12:45:26, Tina Friedrich wrote:
>
>> Yeah, I had that problem as well (trying to set up a partition that
>> didn't have any nodes - they're not here yet). I figured that one can
>> have partitions with nodes that don't exist,
>> though. As in, not even in DNS. I currently have this: [arc-slurm ~]$
>> sinfo
>> PARTITION AVAIL  TIMELIMIT  NODES  STATE NODELIST
>> short        up   12:00:00      1  down* arc-c023
>> short        up   12:00:00      1  alloc arc-c001
>> short        up   12:00:00     43   idle arc-c[002-022,024-045]
>> medium       up 2-00:00:00      0    n/a
>> long*        up   infinite      0    n/a with medium & long partition
>> containing nodes 'arc-c[046-297]': PartitionName=medium
>>    AllowGroups=ALL AllowAccounts=ALL AllowQos=ALL
>>    AllocNodes=ALL Default=NO QoS=N/A
>>    DefaultTime=12:00:00 DisableRootJobs=NO ExclusiveUser=NO GraceTime=0
>> Hidden=NO
>>    MaxNodes=UNLIMITED MaxTime=2-00:00:00 MinNodes=0 LLN=NO
>> MaxCPUsPerNode=UNLIMITED
>>    Nodes=arc-c[046-297]... which don't exist as of today: [arc-slurm ~]$
>> host arc-c046
>> Host arc-c046 not found: 3(NXDOMAIN) which - as you can see - simply ends
>> up with SLURM showing the partition
>> with no nodes. So you could just put a dummy nodename in the slurm.conf
>> file? Tina
>
>
>
> On Fri, 18 Dec 2020 at 11:13, Steve Brasier <steveb at stackhpc.com> wrote:
>
>> Having tried just not even defining any partitions you hit this this
>> <https://github.com/SchedMD/slurm/blob/master/src/common/node_conf.c#L383>check
>> which seems to ensure you can't create a cluster with no nodes. Is it
>> possible to create a control node without any compute nodes, e.g. as part
>> of a staged deployment?
>>
>> http://stackhpc.com/
>> Please note I work Tuesday to Friday.
>>
>>
>> On Fri, 18 Dec 2020 at 10:56, Steve Brasier <steveb at stackhpc.com> wrote:
>>
>>> Hi all,
>>>
>>> According to the relevant manpage
>>> <https://slurm.schedmd.com/archive/slurm-20.02.5/slurm.conf.html> it's
>>> possible to define an empty partition using "Nodes= ".
>>>
>>> However this doesn't seem to work (slurm 20.2.05):
>>>
>>> [centos at testohpc-login-0 ~]$ grep -n Partition /etc/slurm/slurm.conf
>>> 72:PriorityWeightPartition=1000
>>> 105:PartitionName=compute Default=YES MaxTime=86400 State=UP Nodes=
>>>
>>> (note there is a space after that final "=" but I've tried both with and
>>> without)
>>>
>>> [centos at testohpc-login-0 ~]$ sinfo
>>> sinfo: error: Parse error in file /etc/slurm/slurm.conf line 105: "
>>> Nodes= "
>>> sinfo: fatal: Unable to process configuration file
>>>
>>> Is this a bug, or am I doing it wrong?
>>>
>>> thanks for any suggestions
>>>
>>> Steve
>>>
>>> http://stackhpc.com/
>>> Please note I work Tuesday to Friday.
>>>
>>
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