Admission

Kueue’s admission process determines whether a Workload can begin execution.

It involves verifying:

• logical resource availability via quota reservation
• physical resource availability via Topology-Aware Scheduling, when used,
• optional AdmissionChecks for additional admission guards.

Kueue implements this through a two-phase admission cycle:

1. Quota Reservation: When a user submits a Workload, it enters a LocalQueue first. This LocalQueue points to a ClusterQueue which is responsible for managing the available resources. The Kueue checks if the targeted ClusterQueue’s available quota and resource flavors can accomodate requested resources (CPU, memory, GPUs, etc.). If the quota is available, the Kueue reserves resources for this Workload and prevents other Workloads from using the same resources. This phase also includes checking the availability of physical resources when Topology-Aware Scheduling is enabled.

2. Admission Checks: Await for AdmissionChecks configured in the ClusterQueue. Checks can be either built-in such as MultiKueue or ProvisioningRequest, or user-created plugins.

The Workload is admitted once all AdmissionCheckStates are in the Ready state.

Failure Handling:

• For temporary issues (e.g., cloud capacity shortages):

  • The system releases the reserved quota immediately.
  • It requeues the workload.
  • It triggers exponential backoff retries via retryStrategy in ProvisioningRequestConfig.
  • Kueue creates new ProvisioningRequest with -attempt<N> suffix each retry.

• For permanent failures:

  • The system marks the AdmissionCheck as Rejected
  • It evicts the Workload.
  • It releases the reserved quota.
  • It deactivates the Workload and to requeue it, the user needs to set the .status.active field to true.

What’s Next?

You can read the Concepts section to learn how Admission Checks influence admission.