[slurm-users] Node weight / Job Preemption

[Paul Edmon]

I might look at these options:

*preempt_reorder_count=#*
    Specify how many attempts should be made in reording preemptable
    jobs to minimize the count of jobs preempted. The default value is
    1. High values may adversely impact performance. The logic to
    support this option is only available in the select/cons_res and
    select/cons_tres plugins. 
*preempt_strict_order*
    If set, then execute extra logic in an attempt to preempt only the
    lowest priority jobs. It may be desirable to set this configuration
    parameter when there are multiple priorities of preemptable jobs.
    The logic to support this option is only available in the
    select/cons_res and select/cons_tres plugins. 
*preempt_youngest_first*
    If set, then the preemption sorting algorithm will be changed to
    sort by the job start times to favor preempting younger jobs over
    older. (Requires preempt/partition_prio or preempt/qos plugins.) 

In general slurm will try not to preempt if it can avoid it. These 
options can help to guide that a bit more intelligently.

-Paul Edmon-

On 5/29/19 8:53 AM, Mike Harvey wrote:
>
> I am relatively new to SLURM, and am having difficulty configuring our 
> scheduling to behave as we'd like.
>
> Partition based job preemption is configured as follows:
>
> PreemptType=preempt/partition_prio
> PreemptMode=suspend,gang
>
> This has been working fine. However, we recently added an older server 
> to the cluster, and tried to give it a higher weight than our other 
> servers, with the intent that it would only used when resources on 
> other lower-weighted nodes are unavailable. What seems to happen, 
> though, is that a newly submitted job will preempt/suspend a 
> lower-priority job on a lower-weighted node before running on the 
> higher-weighted node. What we would like is for preemption to only 
> occur when no resources are available.
>
> Is this possible?
>
> Thanks,
>
> Mike Harvey
> Systems Administrator
> Bucknell University
> harvey at bucknell.edu <mailto:harvey at bucknell.edu>
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