Deployment controller should count terminating pods in the status

pkg/controller/deployment/sync.go

@@ -27,9 +27,11 @@ import (
 	v1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	utilfeature "k8s.io/apiserver/pkg/util/feature"
 	"k8s.io/klog/v2"
 	"k8s.io/kubernetes/pkg/controller"
 	deploymentutil "k8s.io/kubernetes/pkg/controller/deployment/util"
+	"k8s.io/kubernetes/pkg/features"
 	labelsutil "k8s.io/kubernetes/pkg/util/labels"
 )
 
@@ -504,6 +506,9 @@ func calculateStatus(allRSs []*apps.ReplicaSet, newRS *apps.ReplicaSet, deployme
 		UnavailableReplicas: unavailableReplicas,
 		CollisionCount:      deployment.Status.CollisionCount,
 	}
+	if utilfeature.DefaultFeatureGate.Enabled(features.DeploymentPodReplacementPolicy) {
+		status.TerminatingReplicas = deploymentutil.GetTerminatingReplicaCountForReplicaSets(allRSs)
+	}
 
 	// Copy conditions one by one so we won't mutate the original object.
 	conditions := deployment.Status.Conditions

pkg/controller/deployment/util/deployment_util.go

@@ -714,6 +714,26 @@ func GetAvailableReplicaCountForReplicaSets(replicaSets []*apps.ReplicaSet) int3
 	return totalAvailableReplicas
 }
 
+// GetTerminatingReplicaCountForReplicaSets returns the number of terminating pods for all replica sets
+// or returns an error if any replica sets have been synced by the controller but do not report their terminating count.
+func GetTerminatingReplicaCountForReplicaSets(replicaSets []*apps.ReplicaSet) *int32 {
+	terminatingReplicas := int32(0)
+	for _, rs := range replicaSets {
+		switch {
+		case rs == nil:
+			// No-op
+		case rs.Status.ObservedGeneration == 0 && rs.Status.TerminatingReplicas == nil:
+			// Replicasets that have never been synced by the controller don't contribute to TerminatingReplicas
+		case rs.Status.TerminatingReplicas == nil:
+			// If any replicaset synced by the controller hasn't reported TerminatingReplicas, we cannot calculate a sum
+			return nil
+		default:
+			terminatingReplicas += *rs.Status.TerminatingReplicas
+		}
+	}
+	return &terminatingReplicas
+}
+
 // IsRollingUpdate returns true if the strategy type is a rolling update.
 func IsRollingUpdate(deployment *apps.Deployment) bool {
 	return deployment.Spec.Strategy.Type == apps.RollingUpdateDeploymentStrategyType

pkg/controller/deployment/util/deployment_util_test.go

@@ -57,7 +57,7 @@ func generateRS(deployment apps.Deployment) apps.ReplicaSet {
 	return apps.ReplicaSet{
 		ObjectMeta: metav1.ObjectMeta{
 			UID:             randomUID(),
-			Name:            names.SimpleNameGenerator.GenerateName("replicaset"),
+			Name:            names.SimpleNameGenerator.GenerateName(deployment.Name),
 			Labels:          template.Labels,
 			OwnerReferences: []metav1.OwnerReference{*newDControllerRef(&deployment)},
 		},
@@ -344,42 +344,93 @@ func TestFindOldReplicaSets(t *testing.T) {
 }
 
 func TestGetReplicaCountForReplicaSets(t *testing.T) {
-	rs1 := generateRS(generateDeployment("foo"))
+	rs1 := generateRS(generateDeployment("foo-rs"))
+	rs1.Status.ObservedGeneration = 1
 	*(rs1.Spec.Replicas) = 1
 	rs1.Status.Replicas = 2
-	rs2 := generateRS(generateDeployment("bar"))
+	rs1.Status.TerminatingReplicas = ptr.To[int32](3)
+
+	rs2 := generateRS(generateDeployment("bar-rs"))
+	rs1.Status.ObservedGeneration = 1
 	*(rs2.Spec.Replicas) = 2
 	rs2.Status.Replicas = 3
+	rs2.Status.TerminatingReplicas = ptr.To[int32](1)
+
+	rs3 := generateRS(generateDeployment("unsynced-rs"))
+	*(rs3.Spec.Replicas) = 3
+	rs3.Status.Replicas = 0
+	rs3.Status.TerminatingReplicas = nil
+
+	rs4 := generateRS(generateDeployment("dropped-rs"))
+	rs4.Status.ObservedGeneration = 1
+	*(rs4.Spec.Replicas) = 1
+	rs4.Status.Replicas = 1
+	rs4.Status.TerminatingReplicas = nil
 
 	tests := []struct {
-		Name           string
-		sets           []*apps.ReplicaSet
-		expectedCount  int32
-		expectedActual int32
+		name                string
+		sets                []*apps.ReplicaSet
+		expectedCount       int32
+		expectedActual      int32
+		expectedTerminating *int32
 	}{
 		{
-			"1:2 Replicas",
-			[]*apps.ReplicaSet{&rs1},
-			1,
-			2,
+			name:                "scaling down rs1",
+			sets:                []*apps.ReplicaSet{&rs1},
+			expectedCount:       1,
+			expectedActual:      2,
+			expectedTerminating: ptr.To[int32](3),
 		},
 		{
-			"3:5 Replicas",
-			[]*apps.ReplicaSet{&rs1, &rs2},
-			3,
-			5,
+			name:                "scaling down rs1 and rs2",
+			sets:                []*apps.ReplicaSet{&rs1, &rs2},
+			expectedCount:       3,
+			expectedActual:      5,
+			expectedTerminating: ptr.To[int32](4),
+		},
+		{
+			name:                "scaling up rs3",
+			sets:                []*apps.ReplicaSet{&rs3},
+			expectedCount:       3,
+			expectedActual:      0,
+			expectedTerminating: ptr.To[int32](0),
+		},
+		{
+			name:                "scaling down rs1 and rs2 and scaling up rs3",
+			sets:                []*apps.ReplicaSet{&rs1, &rs2, &rs3},
+			expectedCount:       6,
+			expectedActual:      5,
+			expectedTerminating: ptr.To[int32](4),
+		},
+		{
+			name:                "invalid/unknown terminating status for rs4",
+			sets:                []*apps.ReplicaSet{&rs4},
+			expectedCount:       1,
+			expectedActual:      1,
+			expectedTerminating: nil,
+		},
+		{
+			name:                "invalid/unknown terminating status for rs4 with rs1, rs2 and rs3",
+			sets:                []*apps.ReplicaSet{&rs1, &rs2, &rs3, &rs4},
+			expectedCount:       7,
+			expectedActual:      6,
+			expectedTerminating: nil,
 		},
 	}
 
 	for _, test := range tests {
-		t.Run(test.Name, func(t *testing.T) {
-			rs := GetReplicaCountForReplicaSets(test.sets)
-			if rs != test.expectedCount {
-				t.Errorf("In test case %s, expectedCount %+v, got %+v", test.Name, test.expectedCount, rs)
+		t.Run(test.name, func(t *testing.T) {
+			replicasCount := GetReplicaCountForReplicaSets(test.sets)
+			if replicasCount != test.expectedCount {
+				t.Errorf("expectedCount %d, got %d", test.expectedCount, replicasCount)
 			}
-			rs = GetActualReplicaCountForReplicaSets(test.sets)
-			if rs != test.expectedActual {
-				t.Errorf("In test case %s, expectedActual %+v, got %+v", test.Name, test.expectedActual, rs)
+			actualReplicasCount := GetActualReplicaCountForReplicaSets(test.sets)
+			if actualReplicasCount != test.expectedActual {
+				t.Errorf("expectedActual %d, got %d", test.expectedActual, actualReplicasCount)
+			}
+			terminatingReplicasCount := GetTerminatingReplicaCountForReplicaSets(test.sets)
+			if !ptr.Equal(terminatingReplicasCount, test.expectedTerminating) {
+				t.Errorf("expectedTerminating %d, got %d", ptr.Deref(test.expectedTerminating, -1), ptr.Deref(terminatingReplicasCount, -1))
 			}
 		})
 	}

test/integration/deployment/deployment_test.go

@@ -28,9 +28,12 @@ import (
 	"k8s.io/apimachinery/pkg/util/intstr"
 	"k8s.io/apimachinery/pkg/util/uuid"
 	"k8s.io/apimachinery/pkg/util/wait"
+	utilfeature "k8s.io/apiserver/pkg/util/feature"
 	"k8s.io/client-go/util/retry"
+	featuregatetesting "k8s.io/component-base/featuregate/testing"
 	"k8s.io/klog/v2/ktesting"
 	deploymentutil "k8s.io/kubernetes/pkg/controller/deployment/util"
+	"k8s.io/kubernetes/pkg/features"
 	"k8s.io/kubernetes/test/integration/framework"
 	testutil "k8s.io/kubernetes/test/utils"
 	"k8s.io/utils/ptr"
@@ -965,7 +968,7 @@ func TestDeploymentAvailableCondition(t *testing.T) {
 	}
 
 	// Verify all replicas fields of DeploymentStatus have desired counts
-	if err = tester.checkDeploymentStatusReplicasFields(10, 10, 0, 0, 10); err != nil {
+	if err = tester.checkDeploymentStatusReplicasFields(10, 10, 0, 0, 10, nil); err != nil {
 		t.Fatal(err)
 	}
 
@@ -985,7 +988,7 @@ func TestDeploymentAvailableCondition(t *testing.T) {
 	}
 
 	// Verify all replicas fields of DeploymentStatus have desired counts
-	if err = tester.checkDeploymentStatusReplicasFields(10, 10, 10, 0, 10); err != nil {
+	if err = tester.checkDeploymentStatusReplicasFields(10, 10, 10, 0, 10, nil); err != nil {
 		t.Fatal(err)
 	}
 
@@ -1008,7 +1011,7 @@ func TestDeploymentAvailableCondition(t *testing.T) {
 	}
 
 	// Verify all replicas fields of DeploymentStatus have desired counts
-	if err = tester.checkDeploymentStatusReplicasFields(10, 10, 10, 10, 0); err != nil {
+	if err = tester.checkDeploymentStatusReplicasFields(10, 10, 10, 10, 0, nil); err != nil {
 		t.Fatal(err)
 	}
 }
@@ -1303,3 +1306,98 @@ func TestReplicaSetOrphaningAndAdoptionWhenLabelsChange(t *testing.T) {
 		t.Fatalf("failed waiting for replicaset adoption by deployment %q to complete: %v", deploymentName, err)
 	}
 }
+
+func TestTerminatingReplicasDeploymentStatus(t *testing.T) {
+	featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.DeploymentPodReplacementPolicy, false)
+
+	_, ctx := ktesting.NewTestContext(t)
+	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
+
+	closeFn, rm, dc, informers, c := dcSetup(ctx, t)
+	defer closeFn()
+
+	name := "test-terminating-replica-status"
+	ns := framework.CreateNamespaceOrDie(c, name, t)
+	defer framework.DeleteNamespaceOrDie(c, ns, t)
+
+	deploymentName := "deployment"
+	replicas := int32(6)
+	tester := &deploymentTester{t: t, c: c, deployment: newDeployment(deploymentName, ns.Name, replicas)}
+	tester.deployment.Spec.Strategy.Type = apps.RecreateDeploymentStrategyType
+	tester.deployment.Spec.Strategy.RollingUpdate = nil
+	tester.deployment.Spec.Template.Spec.NodeName = "fake-node"
+	tester.deployment.Spec.Template.Spec.TerminationGracePeriodSeconds = ptr.To(int64(300))
+
+	var err error
+	tester.deployment, err = c.AppsV1().Deployments(ns.Name).Create(context.TODO(), tester.deployment, metav1.CreateOptions{})
+	if err != nil {
+		t.Fatalf("failed to create deployment %q: %v", deploymentName, err)
+	}
+
+	// Start informer and controllers
+	stopControllers := runControllersAndInformers(t, rm, dc, informers)
+	defer stopControllers()
+
+	// Ensure the deployment completes while marking its pods as ready simultaneously
+	if err := tester.waitForDeploymentCompleteAndMarkPodsReady(); err != nil {
+		t.Fatal(err)
+	}
+	// Should not update terminating replicas when feature gate is disabled
+	// Verify all replicas fields of DeploymentStatus have desired counts
+	if err = tester.checkDeploymentStatusReplicasFields(6, 6, 6, 6, 0, nil); err != nil {
+		t.Fatal(err)
+	}
+
+	// Scale down the deployment
+	tester.deployment, err = tester.updateDeployment(func(update *apps.Deployment) {
+		update.Spec.Replicas = ptr.To(int32(4))
+	})
+	if err != nil {
+		t.Fatalf("failed updating deployment %q: %v", deploymentName, err)
+	}
+	// Wait for number of ready replicas to equal number of replicas.
+	if err = tester.waitForReadyReplicas(); err != nil {
+		t.Fatal(err)
+	}
+	// Verify all replicas fields of DeploymentStatus have desired counts
+	if err = tester.checkDeploymentStatusReplicasFields(4, 4, 4, 4, 0, nil); err != nil {
+		t.Fatal(err)
+	}
+
+	// should update terminating replicas when feature gate is enabled
+	featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.DeploymentPodReplacementPolicy, true)
+	// Scale down the deployment
+	tester.deployment, err = tester.updateDeployment(func(update *apps.Deployment) {
+		update.Spec.Replicas = ptr.To(int32(3))
+	})
+	if err != nil {
+		t.Fatalf("failed updating deployment %q: %v", deploymentName, err)
+	}
+	// Wait for number of ready replicas to equal number of replicas.
+	if err = tester.waitForReadyReplicas(); err != nil {
+		t.Fatal(err)
+	}
+	// Verify all replicas fields of DeploymentStatus have desired counts
+	if err = tester.checkDeploymentStatusReplicasFields(3, 3, 3, 3, 0, ptr.To[int32](3)); err != nil {
+		t.Fatal(err)
+	}
+
+	// should not update terminating replicas when feature gate is disabled
+	featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.DeploymentPodReplacementPolicy, false)
+	// Scale down the deployment
+	tester.deployment, err = tester.updateDeployment(func(update *apps.Deployment) {
+		update.Spec.Replicas = ptr.To(int32(2))
+	})
+	if err != nil {
+		t.Fatalf("failed updating deployment %q: %v", deploymentName, err)
+	}
+	// Wait for number of ready replicas to equal number of replicas.
+	if err = tester.waitForReadyReplicas(); err != nil {
+		t.Fatal(err)
+	}
+	// Verify all replicas fields of DeploymentStatus have desired counts
+	if err = tester.checkDeploymentStatusReplicasFields(2, 2, 2, 2, 0, nil); err != nil {
+		t.Fatal(err)
+	}
+}

test/integration/deployment/util.go

@@ -37,6 +37,7 @@ import (
 	"k8s.io/kubernetes/pkg/controller/replicaset"
 	"k8s.io/kubernetes/test/integration/framework"
 	testutil "k8s.io/kubernetes/test/utils"
+	"k8s.io/utils/ptr"
 )
 
 const (
@@ -433,7 +434,7 @@ func (d *deploymentTester) markUpdatedPodsReadyWithoutComplete() error {
 
 // Verify all replicas fields of DeploymentStatus have desired count.
 // Immediately return an error when found a non-matching replicas field.
-func (d *deploymentTester) checkDeploymentStatusReplicasFields(replicas, updatedReplicas, readyReplicas, availableReplicas, unavailableReplicas int32) error {
+func (d *deploymentTester) checkDeploymentStatusReplicasFields(replicas, updatedReplicas, readyReplicas, availableReplicas, unavailableReplicas int32, terminatingReplicas *int32) error {
 	deployment, err := d.c.AppsV1().Deployments(d.deployment.Namespace).Get(context.TODO(), d.deployment.Name, metav1.GetOptions{})
 	if err != nil {
 		return fmt.Errorf("failed to get deployment %q: %v", d.deployment.Name, err)
@@ -448,10 +449,13 @@ func (d *deploymentTester) checkDeploymentStatusReplicasFields(replicas, updated
 		return fmt.Errorf("unexpected .readyReplicas: expect %d, got %d", readyReplicas, deployment.Status.ReadyReplicas)
 	}
 	if deployment.Status.AvailableReplicas != availableReplicas {
-		return fmt.Errorf("unexpected .replicas: expect %d, got %d", availableReplicas, deployment.Status.AvailableReplicas)
+		return fmt.Errorf("unexpected .availableReplicas: expect %d, got %d", availableReplicas, deployment.Status.AvailableReplicas)
 	}
 	if deployment.Status.UnavailableReplicas != unavailableReplicas {
-		return fmt.Errorf("unexpected .replicas: expect %d, got %d", unavailableReplicas, deployment.Status.UnavailableReplicas)
+		return fmt.Errorf("unexpected .unavailableReplicas: expect %d, got %d", unavailableReplicas, deployment.Status.UnavailableReplicas)
+	}
+	if !ptr.Equal(deployment.Status.TerminatingReplicas, terminatingReplicas) {
+		return fmt.Errorf("unexpected .terminatingReplicas: expect %v, got %v", ptr.Deref(terminatingReplicas, -1), ptr.Deref(deployment.Status.TerminatingReplicas, -1))
 	}
 	return nil
 }