Fixes #49445 by introducing a new annotation to attach SG to ELB.

pkg/cloudprovider/providers/aws/aws.go

@@ -142,9 +142,14 @@ const ServiceAnnotationLoadBalancerConnectionIdleTimeout = "service.beta.kuberne
 const ServiceAnnotationLoadBalancerCrossZoneLoadBalancingEnabled = "service.beta.kubernetes.io/aws-load-balancer-cross-zone-load-balancing-enabled"
 
 // ServiceAnnotationLoadBalancerExtraSecurityGroups is the annotation used
-// one the service to specify additional security groups to be added to ELB created
+// on the service to specify additional security groups to be added to ELB created
 const ServiceAnnotationLoadBalancerExtraSecurityGroups = "service.beta.kubernetes.io/aws-load-balancer-extra-security-groups"
 
+// ServiceAnnotationLoadBalancerSecurityGroups is the annotation used
+// on the service to specify the security groups to be added to ELB created. Differently from the annotation
+// "service.beta.kubernetes.io/aws-load-balancer-extra-security-groups", this replaces all other security groups previously assigned to the ELB.
+const ServiceAnnotationLoadBalancerSecurityGroups = "service.beta.kubernetes.io/aws-load-balancer-security-groups"
+
 // ServiceAnnotationLoadBalancerCertificate is the annotation used on the
 // service to request a secure listener. Value is a valid certificate ARN.
 // For more, see http://docs.aws.amazon.com/ElasticLoadBalancing/latest/DeveloperGuide/elb-listener-config.html
@@ -3158,7 +3163,8 @@ func getPortSets(annotation string) (ports *portSets) {
 // attached to ELB created by a service. List always consist of at least
 // 1 member which is an SG created for this service or a SG from the Global config.
 // Extra groups can be specified via annotation, as can extra tags for any
-// new groups.
+// new groups. The annotation "ServiceAnnotationLoadBalancerSecurityGroups" allows for
+// setting the security groups specified.
 func (c *Cloud) buildELBSecurityGroupList(serviceName types.NamespacedName, loadBalancerName string, annotations map[string]string) ([]string, error) {
 	var err error
 	var securityGroupID string
@@ -3175,7 +3181,20 @@ func (c *Cloud) buildELBSecurityGroupList(serviceName types.NamespacedName, load
 			return nil, err
 		}
 	}
-	sgList := []string{securityGroupID}
+
+	sgList := []string{}
+
+	for _, extraSG := range strings.Split(annotations[ServiceAnnotationLoadBalancerSecurityGroups], ",") {
+		extraSG = strings.TrimSpace(extraSG)
+		if len(extraSG) > 0 {
+			sgList = append(sgList, extraSG)
+		}
+	}
+
+	// If no Security Groups have been specified with the ServiceAnnotationLoadBalancerSecurityGroups annotation, we add the default one.
+	if len(sgList) == 0 {
+		sgList = append(sgList, securityGroupID)
+	}
 
 	for _, extraSG := range strings.Split(annotations[ServiceAnnotationLoadBalancerExtraSecurityGroups], ",") {
 		extraSG = strings.TrimSpace(extraSG)

pkg/cloudprovider/providers/aws/aws_test.go

@@ -1179,6 +1179,38 @@ func TestLBExtraSecurityGroupsAnnotation(t *testing.T) {
 	}
 }
 
+func TestLBSecurityGroupsAnnotation(t *testing.T) {
+	awsServices := newMockedFakeAWSServices(TestClusterId)
+	c, _ := newAWSCloud(CloudConfig{}, awsServices)
+
+	sg1 := map[string]string{ServiceAnnotationLoadBalancerSecurityGroups: "sg-000001"}
+	sg2 := map[string]string{ServiceAnnotationLoadBalancerSecurityGroups: "sg-000002"}
+	sg3 := map[string]string{ServiceAnnotationLoadBalancerSecurityGroups: "sg-000001, sg-000002"}
+
+	tests := []struct {
+		name string
+
+		annotations map[string]string
+		expectedSGs []string
+	}{
+		{"SG specified", sg1, []string{sg1[ServiceAnnotationLoadBalancerSecurityGroups]}},
+		{"Multiple SGs specified", sg3, []string{sg1[ServiceAnnotationLoadBalancerSecurityGroups], sg2[ServiceAnnotationLoadBalancerSecurityGroups]}},
+	}
+
+	awsServices.ec2.(*MockedFakeEC2).expectDescribeSecurityGroups(TestClusterId, "k8s-elb-aid", "cluster.test")
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			serviceName := types.NamespacedName{Namespace: "default", Name: "myservice"}
+
+			sgList, err := c.buildELBSecurityGroupList(serviceName, "aid", test.annotations)
+			assert.NoError(t, err, "buildELBSecurityGroupList failed")
+			assert.True(t, sets.NewString(test.expectedSGs...).Equal(sets.NewString(sgList...)),
+				"Security Groups expected=%q , returned=%q", test.expectedSGs, sgList)
+		})
+	}
+}
+
 // Test that we can add a load balancer tag
 func TestAddLoadBalancerTags(t *testing.T) {
 	loadBalancerName := "test-elb"