From 4997ec46623f8e63b59de843fe044b3e8a478967 Mon Sep 17 00:00:00 2001
From: Jose Armesto <github@armesto.net>
Date: Wed, 28 May 2025 16:11:41 +0200
Subject: [PATCH] Update launch template if capacity-block reservation id
 changes

---
 pkg/cloud/services/ec2/launchtemplate.go      | 10 +++++++
 pkg/cloud/services/ec2/launchtemplate_test.go | 30 +++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/pkg/cloud/services/ec2/launchtemplate.go b/pkg/cloud/services/ec2/launchtemplate.go
index 01e81fc013..ead242003a 100644
--- a/pkg/cloud/services/ec2/launchtemplate.go
+++ b/pkg/cloud/services/ec2/launchtemplate.go
@@ -712,6 +712,12 @@ func (s *Service) SDKToLaunchTemplate(d *ec2.LaunchTemplateVersion) (*expinfrav1
 		VersionNumber:     d.VersionNumber,
 	}
 
+	if v.CapacityReservationSpecification != nil &&
+		v.CapacityReservationSpecification.CapacityReservationTarget != nil &&
+		v.CapacityReservationSpecification.CapacityReservationTarget.CapacityReservationId != nil {
+		i.CapacityReservationID = v.CapacityReservationSpecification.CapacityReservationTarget.CapacityReservationId
+	}
+
 	if v.MetadataOptions != nil {
 		i.InstanceMetadataOptions = &infrav1.InstanceMetadataOptions{
 			HTTPPutResponseHopLimit: aws.Int64Value(v.MetadataOptions.HttpPutResponseHopLimit),
@@ -802,6 +808,10 @@ func (s *Service) LaunchTemplateNeedsUpdate(scope scope.LaunchTemplateScope, inc
 		return true, nil
 	}
 
+	if !cmp.Equal(incoming.CapacityReservationID, existing.CapacityReservationID) {
+		return true, nil
+	}
+
 	if !cmp.Equal(incoming.PrivateDNSName, existing.PrivateDNSName) {
 		return true, nil
 	}
diff --git a/pkg/cloud/services/ec2/launchtemplate_test.go b/pkg/cloud/services/ec2/launchtemplate_test.go
index 93fd040f21..99ed68bf45 100644
--- a/pkg/cloud/services/ec2/launchtemplate_test.go
+++ b/pkg/cloud/services/ec2/launchtemplate_test.go
@@ -860,6 +860,36 @@ func TestServiceLaunchTemplateNeedsUpdate(t *testing.T) {
 			want:    true,
 			wantErr: false,
 		},
+		{
+			name: "Should return true if capacity reservation IDs are different",
+			incoming: &expinfrav1.AWSLaunchTemplate{
+				CapacityReservationID: aws.String("new-reservation"),
+			},
+			existing: &expinfrav1.AWSLaunchTemplate{
+				AdditionalSecurityGroups: []infrav1.AWSResourceReference{
+					{ID: aws.String("sg-111")},
+					{ID: aws.String("sg-222")},
+				},
+				CapacityReservationID: aws.String("old-reservation"),
+			},
+			want:    true,
+			wantErr: false,
+		},
+		{
+			name: "Should return true if one has capacity reservation ID and other doesn't",
+			incoming: &expinfrav1.AWSLaunchTemplate{
+				CapacityReservationID: aws.String("new-reservation"),
+			},
+			existing: &expinfrav1.AWSLaunchTemplate{
+				AdditionalSecurityGroups: []infrav1.AWSResourceReference{
+					{ID: aws.String("sg-111")},
+					{ID: aws.String("sg-222")},
+				},
+				CapacityReservationID: nil,
+			},
+			want:    true,
+			wantErr: false,
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {