Why Kueue?

Kueue is a kubernetes-native system that manages quotas and how jobs consume them. Kueue decides when a job should wait, when a job should be admitted to start (as in pods can be created) and when a job should be preempted (as in active pods should be deleted).

Why use Kueue

You can install Kueue on top of a vanilla Kubernetes cluster. Kueue does not replace any existing Kubernetes components. Kueue is compatible with cloud environments where:

  • Compute resources are elastic and can be scaled up and down.
  • Compute resources are heterogeneous (in architecture, availability, price, etc.).

Kueue APIs allow you to express:

  • Quotas and policies for fair sharing among tenants.
  • Resource fungibility: if a resource flavor is fully utilized, Kueue can admit the job using a different flavor.

A core design principle for Kueue is to avoid duplicating mature functionality in Kubernetes components and well-established third-party controllers. Autoscaling, pod-to-node scheduling and job lifecycle management are the responsibility of cluster-autoscaler, kube-scheduler and kube-controller-manager, respectively. Advanced admission control can be delegated to controllers such as gatekeeper.

Features overview

  • Job management: Support job queueing based on priorities with different strategies: StrictFIFO and BestEffortFIFO.
  • Resource management: Support resource fair sharing and preemption with a variety of policies between different tenants.
  • Dynamic resource reclaim: A mechanism to release quota as the pods of a Job complete.
  • Resource flavor fungibility: Quota borrowing or preemption in ClusterQueue and Cohort.
  • Integrations: Built-in support for popular jobs, e.g. BatchJob, Kubeflow training jobs, RayJob, RayCluster, JobSet, plain Pod.
  • System insight: Built-in prometheus metrics to help monitor the state of the system, as well as Conditions.
  • AdmissionChecks: A mechanism for internal or external components to influence whether a workload can be admitted.
  • Advanced autoscaling support: Integration with cluster-autoscaler’s provisioningRequest via admissionChecks.
  • Sequential admission: A simple implementation of all-or-nothing scheduling.
  • Partial admission: Allows jobs to run with a smaller parallelism, based on available quota, if the application supports it.

High-level Kueue operation

High Level Kueue Operation

To learn more about Kueue concepts, see the concepts section.

To learn about different Kueue personas and what you can do with Kueue, see the tasks section.