From 7c2d0b524402810e973a57521e36c706809534f2 Mon Sep 17 00:00:00 2001
From: Vince Prignano <vincepri@redhat.com>
Date: Tue, 10 Oct 2023 16:22:25 -0700
Subject: [PATCH] Allow garbage collector to delete ec2 instances

Signed-off-by: Vince Prignano <vincepri@redhat.com>
---
 api/v1beta2/types.go             |  3 +++
 pkg/cloud/services/gc/cleanup.go |  1 +
 pkg/cloud/services/gc/ec2.go     | 39 ++++++++++++++++++++++++++++++++
 pkg/cloud/services/gc/service.go |  1 +
 4 files changed, 44 insertions(+)

diff --git a/api/v1beta2/types.go b/api/v1beta2/types.go
index 9e77923bbd..b643d2dc36 100644
--- a/api/v1beta2/types.go
+++ b/api/v1beta2/types.go
@@ -83,6 +83,9 @@ const (
 type GCTask string
 
 var (
+	// GCTaskEC2Instance defines a task to cleaning up resources for AWS EC2 instances.
+	GCTaskEC2Instance = GCTask("instance")
+
 	// GCTaskLoadBalancer defines a task to cleaning up resources for AWS load balancers.
 	GCTaskLoadBalancer = GCTask("load-balancer")
 
diff --git a/pkg/cloud/services/gc/cleanup.go b/pkg/cloud/services/gc/cleanup.go
index 27fe88600f..6b0af27dd1 100644
--- a/pkg/cloud/services/gc/cleanup.go
+++ b/pkg/cloud/services/gc/cleanup.go
@@ -72,6 +72,7 @@ func (s *Service) deleteResources(ctx context.Context) error {
 
 	if val, found := annotations.Get(s.scope.InfraCluster(), infrav1.ExternalResourceGCTasksAnnotation); found {
 		var gcTaskToFunc = map[infrav1.GCTask]ResourceCleanupFunc{
+			infrav1.GCTaskEC2Instance:   s.deleteEC2Instances,
 			infrav1.GCTaskLoadBalancer:  s.deleteLoadBalancers,
 			infrav1.GCTaskTargetGroup:   s.deleteTargetGroups,
 			infrav1.GCTaskSecurityGroup: s.deleteSecurityGroups,
diff --git a/pkg/cloud/services/gc/ec2.go b/pkg/cloud/services/gc/ec2.go
index 92e224ff81..878b3c0df2 100644
--- a/pkg/cloud/services/gc/ec2.go
+++ b/pkg/cloud/services/gc/ec2.go
@@ -28,6 +28,45 @@ import (
 	"sigs.k8s.io/cluster-api-provider-aws/v2/pkg/cloud/filter"
 )
 
+func (s *Service) deleteEC2Instances(ctx context.Context, resources []*AWSResource) error {
+	for _, resource := range resources {
+		if !s.isEC2InstanceToDelete(resource) {
+			s.scope.Debug("Resource not an EC2 instance for deletion", "arn", resource.ARN.String())
+			continue
+		}
+
+		instanceID := strings.ReplaceAll(resource.ARN.Resource, "instance/", "")
+		if err := s.deleteEC2Instance(ctx, instanceID); err != nil {
+			return fmt.Errorf("deleting EC2 instance %s: %w", instanceID, err)
+		}
+	}
+	s.scope.Debug("Finished processing resources for EC2 instance deletion")
+
+	return nil
+}
+
+func (s *Service) isEC2InstanceToDelete(resource *AWSResource) bool {
+	if !s.isMatchingResource(resource, ec2.ServiceName, "instance") {
+		return false
+	}
+	if eksClusterName := resource.Tags[eksClusterNameTag]; eksClusterName != "" {
+		s.scope.Debug("EC2 instance was created by EKS directly", "arn", resource.ARN.String(), "check", "instance", "cluster_name", eksClusterName)
+		return false
+	}
+	s.scope.Debug("Resource is an EC2 instance to delete", "arn", resource.ARN.String(), "check", "instance")
+	return true
+}
+
+func (s *Service) deleteEC2Instance(ctx context.Context, instanceID string) error {
+	input := ec2.TerminateInstancesInput{
+		InstanceIds: []*string{aws.String(instanceID)},
+	}
+	if _, err := s.ec2Client.TerminateInstancesWithContext(ctx, &input); err != nil {
+		return fmt.Errorf("terminating EC2 instance: %w", err)
+	}
+	return nil
+}
+
 func (s *Service) deleteSecurityGroups(ctx context.Context, resources []*AWSResource) error {
 	for _, resource := range resources {
 		if !s.isSecurityGroupToDelete(resource) {
diff --git a/pkg/cloud/services/gc/service.go b/pkg/cloud/services/gc/service.go
index 9eb9f789a6..174fc827ea 100644
--- a/pkg/cloud/services/gc/service.go
+++ b/pkg/cloud/services/gc/service.go
@@ -62,6 +62,7 @@ func NewService(clusterScope cloud.ClusterScoper, opts ...ServiceOption) *Servic
 
 func addDefaultCleanupFuncs(s *Service) {
 	s.cleanupFuncs = []ResourceCleanupFunc{
+		s.deleteEC2Instances,
 		s.deleteLoadBalancers,
 		s.deleteTargetGroups,
 		s.deleteSecurityGroups,