[jira] [Assigned] (YUNIKORN-3243) Fair-share queue sorting causes starvation of sibling queues with asymmetric guaranteed resources

["Shubham Mishra (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/YUNIKORN-3243?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Shubham Mishra reassigned YUNIKORN-3243:
----------------------------------------

    Assignee: Shubham Mishra

> Fair-share queue sorting causes starvation of sibling queues with asymmetric guaranteed resources
> -------------------------------------------------------------------------------------------------
>
>                 Key: YUNIKORN-3243
>                 URL: https://issues.apache.org/jira/browse/YUNIKORN-3243
>             Project: Apache YuniKorn
>          Issue Type: Bug
>            Reporter: Shubham Mishra
>            Assignee: Shubham Mishra
>            Priority: Major
>
> When two sibling queues under the same parent have vastly different guaranteed resources (e.g., 3600:1 ratio), the fair-share queue sorting in {{TryAllocate}} causes the smaller queue to be completely starved — its {{app.tryAllocate()}} is never called. This has two consequences:
>  # {*}Scheduling starvation{*}: The smaller queue's asks are never evaluated for allocation, even when nodes have capacity.
>  # {*}Autoscaler blindness{*}: Because {{SetSchedulingAttempted(true)}} is only set inside {{app.tryAllocate()}} (line 1035 of {{{}application.go{}}}), the starved queue's asks never get this flag. {{inspectOutstandingRequests}} skips them, so the cluster autoscaler (e.g., Karpenter) is never notified that capacity is needed.
> The second issue is the more critical one — even if scheduling is delayed, the autoscaler should be able to provision nodes in parallel. But with the current design, the autoscaler signal is gated on queue visitation.
> h3.  



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