Concepts

This section of the documentation helps you learn about the components, APIs and abstractions that Kueue uses to represent your cluster and workloads.

APIs

Resource Flavor

An object that you can define to describe what resources are available in a cluster. Typically, a ResourceFlavor is associated with the characteristics of a group of Nodes. It could distinguish among different characteristics of resources such as availability, pricing, architecture, models, etc.

Cluster Queue

A cluster-scoped resource that governs a pool of resources, defining usage limits and fair sharing rules.

Local Queue

A namespaced resource that groups closely related workloads belonging to a single tenant.

Workload

An application that will run to completion. It is the unit of admission in Kueue. Sometimes referred to as job.

Workload Priority Class

WorkloadPriorityClass defines a priority class for a workload, independently from pod priority.
This priority value from a WorkloadPriorityClass is only used for managing the queueing and preemption of Workloads.

Admission Check

A mechanism allowing internal or external components to influence the timing of workloads admission.

Glossary

Quota Reservation

Quota reservation is the process during through which the kueue scheduler locks the resources needed by a workload within the targeted ClusterQueues ResourceGroups

Quota reservation is sometimes referred to as workload scheduling or job scheduling, but it should not to be confused with pod scheduling.

Admission

Admission is the process of allowing a Workload to start (Pods to be created). A Workload is admitted when it has a Quota Reservation and all its AdmissionCheckStates are Ready.

Cohort

A cohort is a group of ClusterQueues that can borrow unused quota from each other.

Queueing

Queueing is the state of a Workload since the time it is created until it Kueue admits it on a ClusterQueue. Typically, the Workload will compete with other Workloads for available quota based on the fair sharing rules of the ClusterQueue.

Preemption

Preemption is the process of evicting one or more admitted Workloads to accommodate another Workload. The Workload being evicted might be of a lower priority or might be borrowing resources that are now required by the owning ClusterQueue.