Update ASG - do not set desired value for machinepool which have exte…

…rnally managed replicas

exp/controllers/awsmachinepool_controller.go

@@ -49,6 +49,7 @@ import (
 	clusterv1 "sigs.k8s.io/cluster-api/api/v1beta1"
 	expclusterv1 "sigs.k8s.io/cluster-api/exp/api/v1beta1"
 	"sigs.k8s.io/cluster-api/util"
+	"sigs.k8s.io/cluster-api/util/annotations"
 	"sigs.k8s.io/cluster-api/util/conditions"
 	"sigs.k8s.io/cluster-api/util/predicates"
 )
@@ -275,7 +276,7 @@ func (r *AWSMachinePoolReconciler) reconcileNormal(ctx context.Context, machineP
 		return nil
 	}
 
-	if scope.ReplicasExternallyManaged(machinePoolScope.MachinePool) {
+	if annotations.ReplicasManagedByExternalAutoscaler(machinePoolScope.MachinePool) {
 		// Set MachinePool replicas to the ASG DesiredCapacity
 		if *machinePoolScope.MachinePool.Spec.Replicas != *asg.DesiredCapacity {
 			machinePoolScope.Info("Setting MachinePool replicas to ASG DesiredCapacity",
@@ -503,7 +504,7 @@ func (r *AWSMachinePoolReconciler) findASG(machinePoolScope *scope.MachinePoolSc
 func diffASG(machinePoolScope *scope.MachinePoolScope, existingASG *expinfrav1.AutoScalingGroup) string {
 	detectedMachinePoolSpec := machinePoolScope.MachinePool.Spec.DeepCopy()
 
-	if !scope.ReplicasExternallyManaged(machinePoolScope.MachinePool) {
+	if !annotations.ReplicasManagedByExternalAutoscaler(machinePoolScope.MachinePool) {
 		detectedMachinePoolSpec.Replicas = existingASG.DesiredCapacity
 	}
 	if diff := cmp.Diff(machinePoolScope.MachinePool.Spec, *detectedMachinePoolSpec); diff != "" {

exp/controllers/awsmachinepool_controller_test.go

@@ -380,7 +380,7 @@ func TestAWSMachinePoolReconciler(t *testing.T) {
 			ec2Svc.EXPECT().ReconcileTags(gomock.Any(), gomock.Any()).Return(nil).AnyTimes()
 
 			ms.MachinePool.Annotations = map[string]string{
-				scope.ReplicasManagedByAnnotation: scope.ExternalAutoscalerReplicasManagedByAnnotationValue,
+				clusterv1.ReplicasManagedByAnnotation: "somehow-externally-managed",
 			}
 			ms.MachinePool.Spec.Replicas = pointer.Int32(0)
 
@@ -908,7 +908,7 @@ func TestDiffASG(t *testing.T) {
 					MachinePool: &expclusterv1.MachinePool{
 						ObjectMeta: metav1.ObjectMeta{
 							Annotations: map[string]string{
-								scope.ReplicasManagedByAnnotation: scope.ExternalAutoscalerReplicasManagedByAnnotationValue,
+								clusterv1.ReplicasManagedByAnnotation: "", // empty value counts as true (= externally managed)
 							},
 						},
 						Spec: expclusterv1.MachinePoolSpec{

pkg/cloud/scope/machinepool.go

@@ -43,21 +43,6 @@ import (
 	"sigs.k8s.io/cluster-api/util/patch"
 )
 
-const (
-	// ReplicasManagedByAnnotation is an annotation that indicates external (non-Cluster API) management of infra scaling.
-	// The practical effect of this is that the capi "replica" count is derived from the number of observed infra machines,
-	// instead of being a source of truth for eventual consistency.
-	//
-	// N.B. this is to be replaced by a direct reference to CAPI once https://github.com/kubernetes-sigs/cluster-api/pull/7107 is meged.
-	ReplicasManagedByAnnotation = "cluster.x-k8s.io/replicas-managed-by"
-
-	// ExternalAutoscalerReplicasManagedByAnnotationValue is used with the "cluster.x-k8s.io/replicas-managed-by" annotation
-	// to indicate an external autoscaler enforces replica count.
-	//
-	// N.B. this is to be replaced by a direct reference to CAPI once https://github.com/kubernetes-sigs/cluster-api/pull/7107 is meged.
-	ExternalAutoscalerReplicasManagedByAnnotationValue = "external-autoscaler"
-)
-
 // MachinePoolScope defines a scope defined around a machine and its cluster.
 type MachinePoolScope struct {
 	logger.Logger
@@ -404,8 +389,3 @@ func (m *MachinePoolScope) LaunchTemplateName() string {
 func (m *MachinePoolScope) GetRuntimeObject() runtime.Object {
 	return m.AWSMachinePool
 }
-
-func ReplicasExternallyManaged(mp *expclusterv1.MachinePool) bool {
-	val, ok := mp.Annotations[ReplicasManagedByAnnotation]
-	return ok && val == ExternalAutoscalerReplicasManagedByAnnotationValue
-}

pkg/cloud/services/autoscaling/autoscalinggroup.go

@@ -34,6 +34,7 @@ import (
 	"sigs.k8s.io/cluster-api-provider-aws/v2/pkg/cloud/converters"
 	"sigs.k8s.io/cluster-api-provider-aws/v2/pkg/cloud/scope"
 	"sigs.k8s.io/cluster-api-provider-aws/v2/pkg/record"
+	"sigs.k8s.io/cluster-api/util/annotations"
 )
 
 // SDKToAutoScalingGroup converts an AWS EC2 SDK AutoScalingGroup to the CAPA AutoScalingGroup type.
@@ -46,7 +47,7 @@ func (s *Service) SDKToAutoScalingGroup(v *autoscaling.Group) (*expinfrav1.AutoS
 		MaxSize:           int32(aws.Int64Value(v.MaxSize)),
 		MinSize:           int32(aws.Int64Value(v.MinSize)),
 		CapacityRebalance: aws.BoolValue(v.CapacityRebalance),
-		//TODO: determine what additional values go here and what else should be in the struct
+		// TODO: determine what additional values go here and what else should be in the struct
 	}
 
 	if v.VPCZoneIdentifier != nil {
@@ -177,7 +178,7 @@ func (s *Service) CreateASG(machinePoolScope *scope.MachinePoolScope) (*expinfra
 	// Ignore the problem for externally managed clusters because MachinePool replicas will be updated to the right value automatically.
 	if mpReplicas >= machinePoolScope.AWSMachinePool.Spec.MinSize && mpReplicas <= machinePoolScope.AWSMachinePool.Spec.MaxSize {
 		input.DesiredCapacity = &mpReplicas
-	} else if !scope.ReplicasExternallyManaged(machinePoolScope.MachinePool) {
+	} else if !annotations.ReplicasManagedByExternalAutoscaler(machinePoolScope.MachinePool) {
 		return nil, fmt.Errorf("incorrect number of replicas %d in MachinePool %v", mpReplicas, machinePoolScope.MachinePool.Name)
 	}
 
@@ -284,35 +285,35 @@ func (s *Service) DeleteASG(name string) error {
 }
 
 // UpdateASG will update the ASG of a service.
-func (s *Service) UpdateASG(scope *scope.MachinePoolScope) error {
-	subnetIDs, err := s.SubnetIDs(scope)
+func (s *Service) UpdateASG(machinePoolScope *scope.MachinePoolScope) error {
+	subnetIDs, err := s.SubnetIDs(machinePoolScope)
 	if err != nil {
 		return fmt.Errorf("getting subnets for ASG: %w", err)
 	}
 
 	input := &autoscaling.UpdateAutoScalingGroupInput{
-		AutoScalingGroupName: aws.String(scope.Name()), //TODO: define dynamically - borrow logic from ec2
-		MaxSize:              aws.Int64(int64(scope.AWSMachinePool.Spec.MaxSize)),
-		MinSize:              aws.Int64(int64(scope.AWSMachinePool.Spec.MinSize)),
+		AutoScalingGroupName: aws.String(machinePoolScope.Name()), // TODO: define dynamically - borrow logic from ec2
+		MaxSize:              aws.Int64(int64(machinePoolScope.AWSMachinePool.Spec.MaxSize)),
+		MinSize:              aws.Int64(int64(machinePoolScope.AWSMachinePool.Spec.MinSize)),
 		VPCZoneIdentifier:    aws.String(strings.Join(subnetIDs, ",")),
-		CapacityRebalance:    aws.Bool(scope.AWSMachinePool.Spec.CapacityRebalance),
+		CapacityRebalance:    aws.Bool(machinePoolScope.AWSMachinePool.Spec.CapacityRebalance),
 	}
 
-	if scope.MachinePool.Spec.Replicas != nil {
-		input.DesiredCapacity = aws.Int64(int64(*scope.MachinePool.Spec.Replicas))
+	if machinePoolScope.MachinePool.Spec.Replicas != nil && !annotations.ReplicasManagedByExternalAutoscaler(machinePoolScope.MachinePool) {
+		input.DesiredCapacity = aws.Int64(int64(*machinePoolScope.MachinePool.Spec.Replicas))
 	}
 
-	if scope.AWSMachinePool.Spec.MixedInstancesPolicy != nil {
-		input.MixedInstancesPolicy = createSDKMixedInstancesPolicy(scope.Name(), scope.AWSMachinePool.Spec.MixedInstancesPolicy)
+	if machinePoolScope.AWSMachinePool.Spec.MixedInstancesPolicy != nil {
+		input.MixedInstancesPolicy = createSDKMixedInstancesPolicy(machinePoolScope.Name(), machinePoolScope.AWSMachinePool.Spec.MixedInstancesPolicy)
 	} else {
 		input.LaunchTemplate = &autoscaling.LaunchTemplateSpecification{
-			LaunchTemplateId: aws.String(scope.AWSMachinePool.Status.LaunchTemplateID),
+			LaunchTemplateId: aws.String(machinePoolScope.AWSMachinePool.Status.LaunchTemplateID),
 			Version:          aws.String(expinfrav1.LaunchTemplateLatestVersion),
 		}
 	}
 
 	if _, err := s.ASGClient.UpdateAutoScalingGroupWithContext(context.TODO(), input); err != nil {
-		return errors.Wrapf(err, "failed to update ASG %q", scope.Name())
+		return errors.Wrapf(err, "failed to update ASG %q", machinePoolScope.Name())
 	}
 
 	return nil

pkg/cloud/services/autoscaling/autoscalinggroup_test.go

@@ -30,6 +30,7 @@ import (
 	. "github.com/onsi/gomega"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/utils/pointer"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/client/fake"
 
@@ -570,7 +571,7 @@ func TestServiceCreateASG(t *testing.T) {
 				mps.AWSMachinePool.Spec.MaxSize = 5
 				mps.MachinePool.Spec.Replicas = aws.Int32(1)
 				mps.MachinePool.Annotations = map[string]string{
-					scope.ReplicasManagedByAnnotation: scope.ExternalAutoscalerReplicasManagedByAnnotationValue,
+					clusterv1.ReplicasManagedByAnnotation: "", // empty value counts as true (= externally managed)
 				}
 			},
 			wantErr: false,
@@ -592,7 +593,7 @@ func TestServiceCreateASG(t *testing.T) {
 				mps.AWSMachinePool.Spec.MaxSize = 5
 				mps.MachinePool.Spec.Replicas = aws.Int32(6)
 				mps.MachinePool.Annotations = map[string]string{
-					scope.ReplicasManagedByAnnotation: scope.ExternalAutoscalerReplicasManagedByAnnotationValue,
+					clusterv1.ReplicasManagedByAnnotation: "truthy",
 				}
 			},
 			wantErr: false,
@@ -699,17 +700,26 @@ func TestServiceUpdateASG(t *testing.T) {
 		machinePoolName       string
 		setupMachinePoolScope func(*scope.MachinePoolScope)
 		wantErr               bool
-		expect                func(e *mocks.MockEC2APIMockRecorder, m *mock_autoscalingiface.MockAutoScalingAPIMockRecorder)
+		expect                func(e *mocks.MockEC2APIMockRecorder, m *mock_autoscalingiface.MockAutoScalingAPIMockRecorder, g *WithT)
 	}{
 		{
 			name:            "should return without error if update ASG is successful",
 			machinePoolName: "update-asg-success",
 			wantErr:         false,
 			setupMachinePoolScope: func(mps *scope.MachinePoolScope) {
-				mps.AWSMachinePool.Spec.Subnets = nil
+				mps.MachinePool.Spec.Replicas = pointer.Int32(3)
+				mps.AWSMachinePool.Spec.MinSize = 2
+				mps.AWSMachinePool.Spec.MaxSize = 5
 			},
-			expect: func(e *mocks.MockEC2APIMockRecorder, m *mock_autoscalingiface.MockAutoScalingAPIMockRecorder) {
-				m.UpdateAutoScalingGroupWithContext(context.TODO(), gomock.AssignableToTypeOf(&autoscaling.UpdateAutoScalingGroupInput{})).Return(&autoscaling.UpdateAutoScalingGroupOutput{}, nil)
+			expect: func(e *mocks.MockEC2APIMockRecorder, m *mock_autoscalingiface.MockAutoScalingAPIMockRecorder, g *WithT) {
+				m.UpdateAutoScalingGroupWithContext(context.TODO(), gomock.AssignableToTypeOf(&autoscaling.UpdateAutoScalingGroupInput{})).DoAndReturn(func(ctx context.Context, input *autoscaling.UpdateAutoScalingGroupInput, options ...request.Option) (*autoscaling.UpdateAutoScalingGroupOutput, error) {
+					// CAPA should set min/max, and because there's no "externally managed" annotation, also the
+					// "desired" number of instances
+					g.Expect(input.MinSize).To(BeComparableTo(pointer.Int64(2)))
+					g.Expect(input.MaxSize).To(BeComparableTo(pointer.Int64(5)))
+					g.Expect(input.DesiredCapacity).To(BeComparableTo(pointer.Int64(3)))
+					return &autoscaling.UpdateAutoScalingGroupOutput{}, nil
+				})
 			},
 		},
 		{
@@ -719,10 +729,31 @@ func TestServiceUpdateASG(t *testing.T) {
 			setupMachinePoolScope: func(mps *scope.MachinePoolScope) {
 				mps.AWSMachinePool.Spec.MixedInstancesPolicy = nil
 			},
-			expect: func(e *mocks.MockEC2APIMockRecorder, m *mock_autoscalingiface.MockAutoScalingAPIMockRecorder) {
+			expect: func(e *mocks.MockEC2APIMockRecorder, m *mock_autoscalingiface.MockAutoScalingAPIMockRecorder, g *WithT) {
 				m.UpdateAutoScalingGroupWithContext(context.TODO(), gomock.AssignableToTypeOf(&autoscaling.UpdateAutoScalingGroupInput{})).Return(nil, awserrors.NewFailedDependency("dependency failure"))
 			},
 		},
+		{
+			name:            "externally managed replicas annotation",
+			machinePoolName: "update-asg-externally-managed-replicas-annotation",
+			wantErr:         false,
+			setupMachinePoolScope: func(mps *scope.MachinePoolScope) {
+				mps.MachinePool.SetAnnotations(map[string]string{clusterv1.ReplicasManagedByAnnotation: "anything-that-is-not-false"})
+
+				mps.MachinePool.Spec.Replicas = pointer.Int32(40)
+				mps.AWSMachinePool.Spec.MinSize = 20
+				mps.AWSMachinePool.Spec.MaxSize = 50
+			},
+			expect: func(e *mocks.MockEC2APIMockRecorder, m *mock_autoscalingiface.MockAutoScalingAPIMockRecorder, g *WithT) {
+				m.UpdateAutoScalingGroupWithContext(context.TODO(), gomock.AssignableToTypeOf(&autoscaling.UpdateAutoScalingGroupInput{})).DoAndReturn(func(ctx context.Context, input *autoscaling.UpdateAutoScalingGroupInput, options ...request.Option) (*autoscaling.UpdateAutoScalingGroupOutput, error) {
+					// CAPA should set min/max, but not the externally managed "desired" number of instances
+					g.Expect(input.MinSize).To(BeComparableTo(pointer.Int64(20)))
+					g.Expect(input.MaxSize).To(BeComparableTo(pointer.Int64(50)))
+					g.Expect(input.DesiredCapacity).To(BeNil())
+					return &autoscaling.UpdateAutoScalingGroupOutput{}, nil
+				})
+			},
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -733,13 +764,14 @@ func TestServiceUpdateASG(t *testing.T) {
 			g.Expect(err).ToNot(HaveOccurred())
 			ec2Mock := mocks.NewMockEC2API(mockCtrl)
 			asgMock := mock_autoscalingiface.NewMockAutoScalingAPI(mockCtrl)
-			tt.expect(ec2Mock.EXPECT(), asgMock.EXPECT())
+			tt.expect(ec2Mock.EXPECT(), asgMock.EXPECT(), g)
 			s := NewService(clusterScope)
 			s.ASGClient = asgMock
 
 			mps, err := getMachinePoolScope(fakeClient, clusterScope)
 			g.Expect(err).ToNot(HaveOccurred())
 			mps.AWSMachinePool.Name = tt.machinePoolName
+			tt.setupMachinePoolScope(mps)
 
 			err = s.UpdateASG(mps)
 			checkErr(tt.wantErr, err, g)

pkg/cloud/services/eks/nodegroup.go

@@ -34,10 +34,10 @@ import (
 	expinfrav1 "sigs.k8s.io/cluster-api-provider-aws/v2/exp/api/v1beta2"
 	"sigs.k8s.io/cluster-api-provider-aws/v2/pkg/cloud/awserrors"
 	"sigs.k8s.io/cluster-api-provider-aws/v2/pkg/cloud/converters"
-	"sigs.k8s.io/cluster-api-provider-aws/v2/pkg/cloud/scope"
 	"sigs.k8s.io/cluster-api-provider-aws/v2/pkg/cloud/services/wait"
 	"sigs.k8s.io/cluster-api-provider-aws/v2/pkg/record"
 	clusterv1 "sigs.k8s.io/cluster-api/api/v1beta1"
+	"sigs.k8s.io/cluster-api/util/annotations"
 )
 
 func (s *NodegroupService) describeNodegroup() (*eks.Nodegroup, error) {
@@ -533,7 +533,7 @@ func (s *NodegroupService) reconcileNodegroup(ctx context.Context) error {
 		break
 	}
 
-	if scope.ReplicasExternallyManaged(s.scope.MachinePool) {
+	if annotations.ReplicasManagedByExternalAutoscaler(s.scope.MachinePool) {
 		// Set MachinePool replicas to the node group DesiredCapacity
 		ngDesiredCapacity := int32(aws.Int64Value(ng.ScalingConfig.DesiredSize))
 		if *s.scope.MachinePool.Spec.Replicas != ngDesiredCapacity {