Track running backup count via BackupTracker

This avoids an unnecessary apiserver List call when
the backup reconciler is already at capacity.

Signed-off-by: Scott Seago <sseago@redhat.com>

pkg/cmd/server/server.go

@@ -917,6 +917,7 @@ func (s *server) runControllers(defaultVolumeSnapshotLocations map[string]string
 			s.mgr.GetScheme(),
 			s.logger,
 			s.config.ConcurrentBackups,
+			backupTracker,
 		).SetupWithManager(s.mgr); err != nil {
 			s.logger.Fatal(err, "unable to create controller", "controller", constant.ControllerBackupQueue)
 		}

pkg/controller/backup_controller.go

@@ -323,6 +323,8 @@ func (b *backupReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctr
 		switch request.Status.Phase {
 		case velerov1api.BackupPhaseCompleted, velerov1api.BackupPhasePartiallyFailed, velerov1api.BackupPhaseFailed, velerov1api.BackupPhaseFailedValidation:
 			b.backupTracker.Delete(request.Namespace, request.Name)
+		case velerov1api.BackupPhaseWaitingForPluginOperations, velerov1api.BackupPhaseWaitingForPluginOperationsPartiallyFailed, velerov1api.BackupPhaseFinalizing, velerov1api.BackupPhaseFinalizingPartiallyFailed:
+			b.backupTracker.AddPostProcessing(request.Namespace, request.Name)
 		}
 	}()
 

pkg/controller/backup_queue_controller.go

@@ -47,6 +47,7 @@ type backupQueueReconciler struct {
 	Scheme            *runtime.Scheme
 	logger            logrus.FieldLogger
 	concurrentBackups int
+	backupTracker     BackupTracker
 	frequency         time.Duration
 }
 
@@ -60,12 +61,14 @@ func NewBackupQueueReconciler(
 	scheme *runtime.Scheme,
 	logger logrus.FieldLogger,
 	concurrentBackups int,
+	backupTracker BackupTracker,
 ) *backupQueueReconciler {
 	return &backupQueueReconciler{
 		Client:            client,
 		Scheme:            scheme,
 		logger:            logger,
 		concurrentBackups: max(concurrentBackups, 1),
+		backupTracker:     backupTracker,
 		frequency:         defaultQueuedBackupRecheckFrequency,
 	}
 }
@@ -261,11 +264,11 @@ func (r *backupQueueReconciler) Reconcile(ctx context.Context, req ctrl.Request)
 			return ctrl.Result{}, nil
 		}
 		lister := r.newQueuedBackupsLister(allBackups)
-		earlierBackups, runningCount := lister.earlierThan(backup.Status.QueuePosition)
-		if runningCount >= r.concurrentBackups {
+		if r.backupTracker.RunningCount() >= r.concurrentBackups {
 			log.Debugf("%v concurrent backups are already running, leaving %v queued", r.concurrentBackups, backup.Name)
 			return ctrl.Result{}, nil
 		}
+		earlierBackups := lister.earlierThan(backup.Status.QueuePosition)
 		foundConflict, conflictBackup, clusterNamespaces, err := r.detectNamespaceConflict(ctx, backup, earlierBackups)
 		if err != nil {
 			log.WithError(err).Error("error listing namespaces")
@@ -287,6 +290,7 @@ func (r *backupQueueReconciler) Reconcile(ctx context.Context, req ctrl.Request)
 		if err := kube.PatchResource(original, backup, r.Client); err != nil {
 			return ctrl.Result{}, errors.Wrapf(err, "error updating Backup status to %s", backup.Status.Phase)
 		}
+		r.backupTracker.AddReadyToStart(backup.Namespace, backup.Name)
 		log.Debug("Updating queuePosition for remaining queued backups")
 		queuedBackups := lister.orderedQueued()
 		newQueuePos := 1
@@ -329,21 +333,15 @@ func (r *backupQueueReconciler) newQueuedBackupsLister(backupList *velerov1api.B
 	return &queuedBackupsLister{backupList}
 }
 
-func (l *queuedBackupsLister) earlierThan(queuePos int) ([]velerov1api.Backup, int) {
+func (l *queuedBackupsLister) earlierThan(queuePos int) []velerov1api.Backup {
 	backups := []velerov1api.Backup{}
-	runningCount := 0
 	for _, backup := range l.backups.Items {
 		// InProgress and ReadyToStart backups have QueuePosition==0
 		if backup.Status.QueuePosition < queuePos {
 			backups = append(backups, backup)
 		}
-		// InProgress and ReadyToStart backups count towards the concurrentBackups limit
-		if backup.Status.Phase == velerov1api.BackupPhaseInProgress ||
-			backup.Status.Phase == velerov1api.BackupPhaseReadyToStart {
-			runningCount++
-		}
 	}
-	return backups, runningCount
+	return backups
 }
 
 func (l *queuedBackupsLister) orderedQueued() []velerov1api.Backup {

pkg/controller/backup_queue_controller_test.go

@@ -202,9 +202,15 @@ func TestBackupQueueReconciler(t *testing.T) {
 				return
 			}
 
+			backupTracker := NewBackupTracker()
 			initObjs := []runtime.Object{}
 			for _, priorBackup := range test.priorBackups {
 				initObjs = append(initObjs, priorBackup)
+				if priorBackup.Status.Phase == velerov1api.BackupPhaseReadyToStart {
+					backupTracker.AddReadyToStart(priorBackup.Namespace, priorBackup.Name)
+				} else if priorBackup.Status.Phase == velerov1api.BackupPhaseInProgress {
+					backupTracker.Add(priorBackup.Namespace, priorBackup.Name)
+				}
 			}
 			for _, ns := range test.namespaces {
 				initObjs = append(initObjs, builder.ForNamespace(ns).Result())
@@ -214,7 +220,7 @@ func TestBackupQueueReconciler(t *testing.T) {
 			fakeClient := velerotest.NewFakeControllerRuntimeClient(t, initObjs...)
 			logger := logrus.New()
 			log := logger.WithField("controller", "backup-queue-test")
-			r := NewBackupQueueReconciler(fakeClient, scheme, log, test.concurrentBackups)
+			r := NewBackupQueueReconciler(fakeClient, scheme, log, test.concurrentBackups, backupTracker)
 			req := ctrl.Request{NamespacedName: types.NamespacedName{Namespace: test.backup.Namespace, Name: test.backup.Name}}
 			res, err := r.Reconcile(t.Context(), req)
 			gotErr := err != nil

pkg/controller/backup_tracker.go

@@ -25,45 +25,90 @@ import (
 
 // BackupTracker keeps track of in-progress backups.
 type BackupTracker interface {
+	// Add informs the tracker that a backup is ReadyToStart.
+	AddReadyToStart(ns, name string)
 	// Add informs the tracker that a backup is in progress.
 	Add(ns, name string)
-	// Delete informs the tracker that a backup is no longer in progress.
+	// Add informs the tracker that a backup has moved beyond InProgress
+	AddPostProcessing(ns, name string)
+	// Delete informs the tracker that a backup has reached a terminal state.
 	Delete(ns, name string)
-	// Contains returns true if the tracker is tracking the backup.
+	// Contains returns true if backup is InProgress or post-InProgress
 	Contains(ns, name string) bool
+	// RunningCount returns the number of backups which are ReadyToStart or InProgress
+	RunningCount() int
 }
 
 type backupTracker struct {
-	lock    sync.RWMutex
-	backups sets.Set[string]
+	lock                sync.RWMutex
+	readyToStartBackups sets.Set[string]
+	inProgressBackups   sets.Set[string]
+	postProgressBackups sets.Set[string]
 }
 
 // NewBackupTracker returns a new BackupTracker.
 func NewBackupTracker() BackupTracker {
 	return &backupTracker{
-		backups: sets.New[string](),
+		readyToStartBackups: sets.New[string](),
+		inProgressBackups:   sets.New[string](),
+		postProgressBackups: sets.New[string](),
 	}
 }
 
+func (bt *backupTracker) AddReadyToStart(ns, name string) {
+	bt.lock.Lock()
+	defer bt.lock.Unlock()
+
+	bt.readyToStartBackups.Insert(backupTrackerKey(ns, name))
+}
+
 func (bt *backupTracker) Add(ns, name string) {
 	bt.lock.Lock()
 	defer bt.lock.Unlock()
 
-	bt.backups.Insert(backupTrackerKey(ns, name))
+	key := backupTrackerKey(ns, name)
+	bt.readyToStartBackups.Delete(key)
+	bt.inProgressBackups.Insert(key)
+}
+
+func (bt *backupTracker) AddPostProcessing(ns, name string) {
+	bt.lock.Lock()
+	defer bt.lock.Unlock()
+
+	key := backupTrackerKey(ns, name)
+	bt.readyToStartBackups.Delete(key)
+	bt.inProgressBackups.Delete(key)
+	bt.postProgressBackups.Insert(key)
 }
 
 func (bt *backupTracker) Delete(ns, name string) {
 	bt.lock.Lock()
 	defer bt.lock.Unlock()
 
-	bt.backups.Delete(backupTrackerKey(ns, name))
+	key := backupTrackerKey(ns, name)
+	bt.readyToStartBackups.Delete(key)
+	bt.inProgressBackups.Delete(key)
+	bt.postProgressBackups.Delete(key)
 }
 
+// Contains returns true if backup is InProgress or post-InProgress
+// ignores ReadyToStart, since this is used to determine whether
+// a backup is in progress and thus not able to be deleted now.
 func (bt *backupTracker) Contains(ns, name string) bool {
 	bt.lock.RLock()
 	defer bt.lock.RUnlock()
 
-	return bt.backups.Has(backupTrackerKey(ns, name))
+	key := backupTrackerKey(ns, name)
+	return bt.inProgressBackups.Has(key) || bt.postProgressBackups.Has(key)
+}
+
+// RunningCount returns the number of backups which are ReadyToStart or InProgress
+// used by queue controller to determine whether a new backup can be started.
+func (bt *backupTracker) RunningCount() int {
+	bt.lock.RLock()
+	defer bt.lock.RUnlock()
+
+	return bt.inProgressBackups.Len() + bt.readyToStartBackups.Len()
 }
 
 func backupTrackerKey(ns, name string) string {