Priority-based exclusive placement

api/jobset/v1alpha2/jobset_types.go

@@ -42,6 +42,7 @@ const (
 	// job placement per topology group (defined as the label value).
 	// If set at the ReplicatedJob level, all child jobs from the target ReplicatedJobs will be scheduled
 	// using exclusive job placement per topology group.
+	// Exclusive placement is enforced within a priority level.
 	ExclusiveKey string = "alpha.jobset.sigs.k8s.io/exclusive-topology"
 	// NodeSelectorStrategyKey is an annotation that acts as a flag, the value does not matter.
 	// If set, the JobSet controller will automatically inject nodeSelectors for the JobSetNameKey label to

go.mod

@@ -1,6 +1,6 @@
 module sigs.k8s.io/jobset
 
-go 1.22.0
+go 1.23
 
 require (
 	github.com/google/go-cmp v0.6.0

pkg/constants/constants.go

@@ -28,6 +28,10 @@ const (
 	// the JobSet is currently on.
 	RestartsKey = "jobset.sigs.k8s.io/restart-attempt"
 
+	// PriorityKey is a label key to record the pod priority. This is needed to enfroce exclusive placement
+	// only among jobs within the same priority.
+	PriorityKey = "jobset.sigs.k8s.io/priority"
+
 	// MaxParallelism defines the maximum number of parallel Job creations/deltions that
 	// the JobSet controller can perform.
 	MaxParallelism = 50

pkg/webhooks/pod_mutating_webhook.go

@@ -27,6 +27,7 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/webhook/admission"
 
 	jobset "sigs.k8s.io/jobset/api/jobset/v1alpha2"
+	"sigs.k8s.io/jobset/pkg/constants"
 )
 
 // +kubebuilder:webhook:path=/mutate--v1-pod,mutating=true,failurePolicy=fail,groups="",resources=pods,verbs=create,versions=v1,name=mpod.kb.io,sideEffects=None,admissionReviewVersions=v1
@@ -82,6 +83,9 @@ func (p *podWebhook) Default(ctx context.Context, obj runtime.Object) error {
 // scheduled on.
 func (p *podWebhook) patchPod(ctx context.Context, pod *corev1.Pod) error {
 	log := ctrl.LoggerFrom(ctx)
+	if pod.Spec.Priority != nil {
+		pod.Labels[constants.PriorityKey] = fmt.Sprint(*pod.Spec.Priority)
+	}
 	if pod.Annotations[batchv1.JobCompletionIndexAnnotation] == "0" {
 		log.V(3).Info(fmt.Sprintf("pod webhook: setting exclusive affinities for pod: %s", pod.Name))
 		setExclusiveAffinities(pod)
@@ -128,6 +132,11 @@ func setExclusiveAffinities(pod *corev1.Pod) {
 					Operator: metav1.LabelSelectorOpNotIn,
 					Values:   []string{pod.Labels[jobset.JobKey]},
 				},
+				{
+					Key:      constants.PriorityKey,
+					Operator: metav1.LabelSelectorOpIn,
+					Values:   []string{pod.Labels[constants.PriorityKey]},
+				},
 			}},
 			TopologyKey:       pod.Annotations[jobset.ExclusiveKey],
 			NamespaceSelector: &metav1.LabelSelector{},