scheduler: correct dated comments on pod preemption

- correct wordings related with annotations - which hasn't been used since alpha version

Author: Huang-Wei

pkg/scheduler/factory/factory.go

@@ -90,7 +90,8 @@ type Config struct {
 	// with scheduling, PodScheduled condition will be updated in apiserver in /bind
 	// handler so that binding and setting PodCondition it is atomic.
 	PodConditionUpdater PodConditionUpdater
-	// PodPreemptor is used to evict pods and update pod annotations.
+	// PodPreemptor is used to evict pods and update 'NominatedNode' field of
+	// the preemptor pod.
 	PodPreemptor PodPreemptor
 	// PlugingSet has a set of plugins and data used to run them.
 	PluginSet pluginsv1alpha1.PluginSet
@@ -125,8 +126,8 @@ type Config struct {
 	SchedulingQueue internalqueue.SchedulingQueue
 }
 
-// PodPreemptor has methods needed to delete a pod and to update
-// annotations of the preemptor pod.
+// PodPreemptor has methods needed to delete a pod and to update 'NominatedPod'
+// field of the preemptor pod.
 type PodPreemptor interface {
 	GetUpdatedPod(pod *v1.Pod) (*v1.Pod, error)
 	DeletePod(pod *v1.Pod) error

pkg/scheduler/scheduler.go

@@ -285,7 +285,7 @@ func (sched *Scheduler) schedule(pod *v1.Pod) (core.ScheduleResult, error) {
 }
 
 // preempt tries to create room for a pod that has failed to schedule, by preempting lower priority pods if possible.
-// If it succeeds, it adds the name of the node where preemption has happened to the pod annotations.
+// If it succeeds, it adds the name of the node where preemption has happened to the pod spec.
 // It returns the node name and an error if any.
 func (sched *Scheduler) preempt(preemptor *v1.Pod, scheduleErr error) (string, error) {
 	preemptor, err := sched.config.PodPreemptor.GetUpdatedPod(preemptor)
@@ -310,7 +310,7 @@ func (sched *Scheduler) preempt(preemptor *v1.Pod, scheduleErr error) (string, e
 		// Make a call to update nominated node name of the pod on the API server.
 		err = sched.config.PodPreemptor.SetNominatedNodeName(preemptor, nodeName)
 		if err != nil {
-			klog.Errorf("Error in preemption process. Cannot update pod %v/%v annotations: %v", preemptor.Namespace, preemptor.Name, err)
+			klog.Errorf("Error in preemption process. Cannot set 'NominatedPod' on pod %v/%v: %v", preemptor.Namespace, preemptor.Name, err)
 			sched.config.SchedulingQueue.DeleteNominatedPodIfExists(preemptor)
 			return "", err
 		}
@@ -327,11 +327,12 @@ func (sched *Scheduler) preempt(preemptor *v1.Pod, scheduleErr error) (string, e
 	// Clearing nominated pods should happen outside of "if node != nil". Node could
 	// be nil when a pod with nominated node name is eligible to preempt again,
 	// but preemption logic does not find any node for it. In that case Preempt()
-	// function of generic_scheduler.go returns the pod itself for removal of the annotation.
+	// function of generic_scheduler.go returns the pod itself for removal of
+	// the 'NominatedPod' field.
 	for _, p := range nominatedPodsToClear {
 		rErr := sched.config.PodPreemptor.RemoveNominatedNodeName(p)
 		if rErr != nil {
-			klog.Errorf("Cannot remove nominated node annotation of pod: %v", rErr)
+			klog.Errorf("Cannot remove 'NominatedPod' field of pod: %v", rErr)
 			// We do not return as this error is not critical.
 		}
 	}