Return the active leases from ActiveLeases

The lease counter needs to hand over more than a number to its
consumers, so it needs the leases themselves. Let ActiveLeases return
the active controller leases and let the callers count them. Split out
the selection of controller leases and the activity check, so that the
lease counter can observe leases that aren't active, too.

Signed-off-by: Tom Wieczorek <twieczorek@mirantis.com>

pkg/autopilot/controller/updates/clusterinfo.go

@@ -121,10 +121,11 @@ func (c *ClusterInfoCollector) CollectData(ctx context.Context) (*ClusterInfo, e
 	}
 
 	// Collect control plane node count
-	ci.ControlPlaneNodesCount, err = leasecounter.ActiveLeases(ctx, c.client)
+	activeLeases, err := leasecounter.ActiveLeases(ctx, c.client)
 	if err != nil {
 		return ci, fmt.Errorf("can't collect control plane nodes count: %w", err)
 	}
+	ci.ControlPlaneNodesCount = uint(len(activeLeases))
 
 	return ci, nil
 }

pkg/component/controller/leasecounter/component.go

@@ -111,12 +111,12 @@ func (c *Component) runLeaseCounter(ctx context.Context, clients kubernetes.Inte
 		c.log.Debug("Counting active controller leases")
 		ctx, cancel := context.WithTimeout(ctx, 10*time.Second)
 		defer cancel()
-		numActiveLeases, err := ActiveLeases(ctx, clients)
+		activeLeases, err := ActiveLeases(ctx, clients)
 		if err != nil {
 			c.log.WithError(err).Error("Failed to count controller lease holders")
 			return
 		}
 
-		c.UpdateControllerCount(numActiveLeases)
+		c.UpdateControllerCount(uint(len(activeLeases)))
 	}, 10*time.Second)
 }

pkg/component/controller/leasecounter/util.go

@@ -9,26 +9,46 @@ import (
 
 	kubeutil "github.com/k0sproject/k0s/pkg/kubernetes"
 
+	coordinationv1 "k8s.io/api/coordination/v1"
 	corev1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/client-go/kubernetes"
 )
 
-// Counts the active controller leases.
-func ActiveLeases(ctx context.Context, kubeClient kubernetes.Interface) (count uint, _ error) {
-	leases, err := kubeClient.CoordinationV1().Leases(corev1.NamespaceNodeLease).List(ctx, metav1.ListOptions{})
+// Returns the active controller leases.
+func ActiveLeases(ctx context.Context, kubeClient kubernetes.Interface) (activeLeases []coordinationv1.Lease, _ error) {
+	allLeases, err := controllerLeases(ctx, kubeClient)
 	if err != nil {
-		return 0, err
+		return nil, err
 	}
-	for _, l := range leases.Items {
-		switch {
-		// FIXME: Remove the name prefix check in k0s 1.38+.
-		case l.Labels[leaseTypeLabel] != leaseTypeLabelValueController && !strings.HasPrefix(l.Name, "k0s-ctrl-"):
-		case l.Spec.HolderIdentity == nil || *l.Spec.HolderIdentity == "":
-		case kubeutil.IsValidLease(l):
-			count++
+
+	for _, l := range allLeases {
+		if isActive(&l) {
+			activeLeases = append(activeLeases, l)
 		}
 	}
 
-	return count, nil
+	return
+}
+
+// Returns all controller leases, active or not.
+func controllerLeases(ctx context.Context, kubeClient kubernetes.Interface) (leases []coordinationv1.Lease, _ error) {
+	allLeases, err := kubeClient.CoordinationV1().Leases(corev1.NamespaceNodeLease).List(ctx, metav1.ListOptions{})
+	if err != nil {
+		return nil, err
+	}
+
+	for _, l := range allLeases.Items {
+		// FIXME: Remove the name prefix check in k0s 1.38+.
+		if l.Labels[leaseTypeLabel] == leaseTypeLabelValueController || strings.HasPrefix(l.Name, "k0s-ctrl-") {
+			leases = append(leases, l)
+		}
+	}
+
+	return
+}
+
+// Indicates if the lease is held and hasn't expired.
+func isActive(l *coordinationv1.Lease) bool {
+	return l.Spec.HolderIdentity != nil && *l.Spec.HolderIdentity != "" && kubeutil.IsValidLease(*l)
 }

pkg/component/controller/leasecounter/util_test.go

@@ -22,7 +22,7 @@ func TestActiveLeases(t *testing.T) {
 
 	for _, tt := range []struct {
 		name     string
-		expected uint
+		expected int
 		leases   []runtime.Object
 	}{
 		{
@@ -34,7 +34,7 @@ func TestActiveLeases(t *testing.T) {
 			1, []runtime.Object{makeLease(withoutControllerLabel, withName("k0s-ctrl-foo"))},
 		},
 		{
-			"returns zero when there are no leases",
+			"returns no leases when there are none",
 			0, nil,
 		},
 		{
@@ -73,9 +73,9 @@ func TestActiveLeases(t *testing.T) {
 	} {
 		t.Run(tt.name, func(t *testing.T) {
 			c := fake.NewSimpleClientset(tt.leases...)
-			count, err := ActiveLeases(t.Context(), c)
+			leases, err := ActiveLeases(t.Context(), c)
 			assert.NoError(t, err)
-			assert.Equal(t, tt.expected, count)
+			assert.Len(t, leases, tt.expected)
 		})
 	}
 }

pkg/telemetry/telemetry.go

@@ -68,10 +68,11 @@ func (c *Component) collectTelemetry(ctx context.Context, clients kubernetes.Int
 	data.WorkerData = wds
 	data.MEMTotal = sums.memTotal
 	data.CPUTotal = sums.cpuTotal
-	data.ControlPlaneNodesCount, err = leasecounter.ActiveLeases(ctx, clients)
+	activeLeases, err := leasecounter.ActiveLeases(ctx, clients)
 	if err != nil {
 		return data, fmt.Errorf("can't collect control plane nodes count: %w", err)
 	}
+	data.ControlPlaneNodesCount = uint(len(activeLeases))
 	return data, nil
 }