perform scale up if no candidate leases are present (#113)

Co-authored-by: Rishabh Patel <[email protected]>

internal/prober/prober.go

@@ -118,12 +118,7 @@ func (p *Prober) probe(ctx context.Context) {
 	if err != nil {
 		return
 	}
-	if len(candidateNodeLeases) == 0 {
-		p.l.Info("No owned node leases are present in the cluster, skipping scaling operation")
-		return
-	}
 	if p.shouldPerformScaleUp(candidateNodeLeases) {
-		p.l.Info("Lease probe succeeded, performing scale up operation if required")
 		if err = p.scaler.ScaleUp(ctx); err != nil {
 			p.l.Error(err, "Failed to scale up resources")
 		}
@@ -139,13 +134,21 @@ func (p *Prober) probe(ctx context.Context) {
 // shouldPerformScaleUp returns true if the ratio of expired node leases to valid node leases is less than
 // the NodeLeaseFailureFraction set in the prober config
 func (p *Prober) shouldPerformScaleUp(candidateNodeLeases []coordinationv1.Lease) bool {
+	if len(candidateNodeLeases) == 0 {
+		p.l.Info("No owned node leases are present in the cluster, performing scale up operation if required")
+		return true
+	}
 	var expiredNodeLeaseCount float64
 	for _, lease := range candidateNodeLeases {
 		if p.isLeaseExpired(lease) {
 			expiredNodeLeaseCount++
 		}
 	}
-	return expiredNodeLeaseCount/float64(len(candidateNodeLeases)) < *p.config.NodeLeaseFailureFraction
+	shouldScaleUp := expiredNodeLeaseCount/float64(len(candidateNodeLeases)) < *p.config.NodeLeaseFailureFraction
+	if shouldScaleUp {
+		p.l.Info("Lease probe succeeded, performing scale up operation if required")
+	}
+	return shouldScaleUp
 }
 
 func (p *Prober) setupProbeClient(ctx context.Context, namespace string, kubeConfigSecretName string) (kubernetes.Interface, error) {

internal/prober/prober_test.go

@@ -181,11 +181,13 @@ func TestAPIServerProbeShouldNotRunIfClientNotCreated(t *testing.T) {
 	createAndRunProber(t, testProbeInterval.Duration, config, mocks)
 }
 
-func TestScalingShouldNotHappenIfNoOwnedLeasesPresent(t *testing.T) {
+func TestScaleUpShouldHappenIfNoOwnedLeasesPresent(t *testing.T) {
 	entry := probeTestCase{
-		name:      "lease probe should reset if no owned lease is present",
-		leaseList: createNodeLeases(nil),
-		nodeList:  createNodes(0),
+		name:            "scale up should happen if no owned lease is present",
+		leaseList:       createNodeLeases(nil),
+		nodeList:        createNodes(0),
+		minScaleUpCount: 1,
+		maxScaleUpCount: math.MaxInt8,
 	}
 	mocks := createAndInitializeMocks(t, entry)
 	config := createConfig(testProbeInterval, metav1.Duration{Duration: time.Microsecond}, metav1.Duration{Duration: 40 * time.Second}, 0.2)