Use AWSMachinePool Spec subnet filters to fetch subnet IDs

Co-authored-by: calvix
Co-authored-by: Shivani Singhal <[email protected]>

exp/api/v1beta1/awsmachinepool_webhook.go

@@ -81,6 +81,23 @@ func (r *AWSMachinePool) validateRootVolume() field.ErrorList {
 	return allErrs
 }
 
+func (r *AWSMachinePool) validateSubnets() field.ErrorList {
+	var allErrs field.ErrorList
+
+	if r.Spec.Subnets == nil {
+		return allErrs
+	}
+
+	for _, subnet := range r.Spec.Subnets {
+		if subnet.ID != nil && subnet.Filters != nil {
+			allErrs = append(allErrs, field.Forbidden(field.NewPath("spec.subnets.filters"), "providing either subnet ID or filter is supported, should not provide both"))
+			break
+		}
+	}
+
+	return allErrs
+}
+
 // ValidateCreate will do any extra validation when creating a AWSMachinePool.
 func (r *AWSMachinePool) ValidateCreate() error {
 	log.Info("AWSMachinePool validate create", "name", r.Name)
@@ -90,6 +107,7 @@ func (r *AWSMachinePool) ValidateCreate() error {
 	allErrs = append(allErrs, r.validateDefaultCoolDown()...)
 	allErrs = append(allErrs, r.validateRootVolume()...)
 	allErrs = append(allErrs, r.Spec.AdditionalTags.Validate()...)
+	allErrs = append(allErrs, r.validateSubnets()...)
 
 	if len(allErrs) == 0 {
 		return nil
@@ -108,6 +126,7 @@ func (r *AWSMachinePool) ValidateUpdate(old runtime.Object) error {
 
 	allErrs = append(allErrs, r.validateDefaultCoolDown()...)
 	allErrs = append(allErrs, r.Spec.AdditionalTags.Validate()...)
+	allErrs = append(allErrs, r.validateSubnets()...)
 
 	if len(allErrs) == 0 {
 		return nil

pkg/cloud/scope/machinepool.go

@@ -21,7 +21,6 @@ import (
 	"fmt"
 	"strings"
 
-	"github.com/aws/aws-sdk-go/aws"
 	"github.com/go-logr/logr"
 	"github.com/pkg/errors"
 	corev1 "k8s.io/api/core/v1"
@@ -222,12 +221,7 @@ func (m *MachinePoolScope) IsEKSManaged() bool {
 }
 
 // SubnetIDs returns the machine pool subnet IDs.
-func (m *MachinePoolScope) SubnetIDs() ([]string, error) {
-	subnetIDs := make([]string, len(m.AWSMachinePool.Spec.Subnets))
-	for i, v := range m.AWSMachinePool.Spec.Subnets {
-		subnetIDs[i] = aws.StringValue(v.ID)
-	}
-
+func (m *MachinePoolScope) SubnetIDs(subnetIDs []string) ([]string, error) {
 	strategy, err := newDefaultSubnetPlacementStrategy(&m.Logger)
 	if err != nil {
 		return subnetIDs, fmt.Errorf("getting subnet placement strategy: %w", err)

pkg/cloud/services/autoscaling/autoscalinggroup.go

@@ -22,6 +22,7 @@ import (
 
 	"github.com/aws/aws-sdk-go/aws"
 	"github.com/aws/aws-sdk-go/service/autoscaling"
+	"github.com/aws/aws-sdk-go/service/ec2"
 	"github.com/pkg/errors"
 	"k8s.io/utils/pointer"
 
@@ -144,7 +145,7 @@ func (s *Service) GetASGByName(scope *scope.MachinePoolScope) (*expinfrav1.AutoS
 
 // CreateASG runs an autoscaling group.
 func (s *Service) CreateASG(scope *scope.MachinePoolScope) (*expinfrav1.AutoScalingGroup, error) {
-	subnets, err := scope.SubnetIDs()
+	subnets, err := s.SubnetIDs(scope)
 	if err != nil {
 		return nil, fmt.Errorf("getting subnets for ASG: %w", err)
 	}
@@ -267,15 +268,9 @@ func (s *Service) DeleteASG(name string) error {
 
 // UpdateASG will update the ASG of a service.
 func (s *Service) UpdateASG(scope *scope.MachinePoolScope) error {
-	subnetIDs := make([]string, len(scope.AWSMachinePool.Spec.Subnets))
-	for i, v := range scope.AWSMachinePool.Spec.Subnets {
-		subnetIDs[i] = aws.StringValue(v.ID)
-	}
-
-	if len(subnetIDs) == 0 {
-		for _, subnet := range scope.InfraCluster.Subnets() {
-			subnetIDs = append(subnetIDs, subnet.ID)
-		}
+	subnetIDs, err := s.SubnetIDs(scope)
+	if err != nil {
+		return fmt.Errorf("getting subnets for ASG: %w", err)
 	}
 
 	input := &autoscaling.UpdateAutoScalingGroupInput{
@@ -465,3 +460,38 @@ func mapToTags(input map[string]string, resourceID *string) []*autoscaling.Tag {
 	}
 	return tags
 }
+
+// SubnetIDs return subnet IDs of a AWSMachinePool based on given subnetIDs and filters.
+func (s *Service) SubnetIDs(scope *scope.MachinePoolScope) ([]string, error) {
+	subnetIDs := make([]string, 0)
+	var inputFilters = make([]*ec2.Filter, 0)
+
+	for _, subnet := range scope.AWSMachinePool.Spec.Subnets {
+		switch {
+		case subnet.ID != nil:
+			subnetIDs = append(subnetIDs, aws.StringValue(subnet.ID))
+		case subnet.Filters != nil:
+			for _, eachFilter := range subnet.Filters {
+				inputFilters = append(inputFilters, &ec2.Filter{
+					Name:   aws.String(eachFilter.Name),
+					Values: aws.StringSlice(eachFilter.Values),
+				})
+			}
+		}
+	}
+
+	if len(inputFilters) > 0 {
+		out, err := s.EC2Client.DescribeSubnets(&ec2.DescribeSubnetsInput{
+			Filters: inputFilters,
+		})
+		if err != nil {
+			return nil, err
+		}
+
+		for _, subnet := range out.Subnets {
+			subnetIDs = append(subnetIDs, *subnet.SubnetId)
+		}
+	}
+
+	return scope.SubnetIDs(subnetIDs)
+}