Skip to content

Configuring fair sharing

Fair sharing is a preemption strategy that is used to achieve an equal or weighted share of borrowable resources between the tenants of a cohort. Borrowable resources are the unused nominal quota of all the cluster queues in a cohort.

You can configure fair sharing by setting the preemptionPolicy value in the Kueue custom resource (CR) to FairSharing.

Cluster queue weights

After you have enabled fair sharing, you must set share values for each cluster queue before fair sharing can take place. Share values are represented as the weight value in a ClusterQueue object.

Share values are important because they allow administrators to prioritize specific job types or teams. Critical applications or high-priority teams can be configured with a weighted value so that they receive a proportionally larger share of the available resources. Configuring weights ensures that unused resources are distributed according to defined organizational or project priorities rather than on a first-come, first-served basis.

The weight value, or share value, defines a comparative advantage for the cluster queue when competing for borrowable resources. Generally, Red Hat build of Kueue admits jobs with a lower share value first. Jobs with a higher share value are more likely to be preempted before those with lower share values.

Example cluster queue with a fair sharing weight configured
apiVersion: kueue.x-k8s.io/v1beta1
kind: ClusterQueue
metadata:
  name: cluster-queue
spec:
  namespaceSelector: {}
  resourceGroups:
  - coveredResources: ["cpu"]
    flavors:
    - name: default-flavor
      resources:
      - name: cpu
        nominalQuota: 9
  cohort: example-cohort
  fairSharing:
    weight: 2

Zero weight

A weight value of 0 represents an infinite share value. This means that the cluster queue is always at a disadvantage compared to others, and its workloads are always the first to be preempted when fair sharing is enabled.

Additional resources