Add ip_address_type support to elbv2 target group

.changelog/26320.txt

@@ -0,0 +1,3 @@
+```release-note:enhancement
+resource/aws_lb_target_group: Add `ip_address_type` argument
+```

internal/service/elbv2/target_group.go

@@ -256,6 +256,13 @@ func ResourceTargetGroup() *schema.Resource {
 					},
 				},
 			},
+			"ip_address_type": {
+				Type:         schema.TypeString,
+				Optional:     true,
+				Computed:     true,
+				ForceNew:     true,
+				ValidateFunc: validation.StringInSlice(elbv2.TargetGroupIpAddressTypeEnum_Values(), false),
+			},
 			"target_type": {
 				Type:         schema.TypeString,
 				Optional:     true,
@@ -318,6 +325,12 @@ func resourceTargetGroupCreate(d *schema.ResourceData, meta interface{}) error {
 			params.ProtocolVersion = aws.String(d.Get("protocol_version").(string))
 		}
 		params.VpcId = aws.String(d.Get("vpc_id").(string))
+
+		if d.Get("target_type").(string) == elbv2.TargetTypeEnumIp {
+			if _, ok := d.GetOk("ip_address_type"); ok {
+				params.IpAddressType = aws.String(d.Get("ip_address_type").(string))
+			}
+		}
 	}
 
 	if healthChecks := d.Get("health_check").([]interface{}); len(healthChecks) == 1 {

internal/service/elbv2/target_group_test.go

@@ -254,6 +254,29 @@ func TestAccELBV2TargetGroup_HealthCheck_tcp(t *testing.T) {
 	})
 }
 
+func TestAccELBV2TargetGroup_ipAddressType(t *testing.T) {
+	var targetGroup1 elbv2.TargetGroup
+	rName := sdkacctest.RandomWithPrefix(acctest.ResourcePrefix)
+	resourceName := "aws_lb_target_group.test"
+
+	resource.ParallelTest(t, resource.TestCase{
+		PreCheck:                 func() { acctest.PreCheck(t) },
+		ErrorCheck:               acctest.ErrorCheck(t, elbv2.EndpointsID),
+		ProtoV5ProviderFactories: acctest.ProtoV5ProviderFactories,
+		CheckDestroy:             testAccCheckTargetGroupDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccTargetGroupConfig_ipAddressType(rName),
+				Check: resource.ComposeAggregateTestCheckFunc(
+					testAccCheckTargetGroupExists(resourceName, &targetGroup1),
+					resource.TestCheckResourceAttr(resourceName, "target_type", "ip"),
+					resource.TestCheckResourceAttr(resourceName, "ip_address_type", "ipv6"),
+				),
+			},
+		},
+	})
+}
+
 func TestAccELBV2TargetGroup_tls(t *testing.T) {
 	var targetGroup1 elbv2.TargetGroup
 	rName := sdkacctest.RandomWithPrefix(acctest.ResourcePrefix)
@@ -2351,6 +2374,40 @@ resource "aws_vpc" "test" {
 `, rName)
 }
 
+func testAccTargetGroupConfig_ipAddressType(rName string) string {
+	return fmt.Sprintf(`
+resource "aws_vpc" "test" {
+  cidr_block = "10.0.0.0/16"
+
+  tags = {
+    Name = %[1]q
+  }
+}
+
+resource "aws_lb_target_group" "test" {
+  name     = %[1]q
+  port     = 443
+  protocol = "TLS"
+  vpc_id   = aws_vpc.test.id
+
+  target_type     = "ip"
+  ip_address_type = "ipv6"
+
+  health_check {
+    interval            = 10
+    port                = "traffic-port"
+    protocol            = "TCP"
+    healthy_threshold   = 3
+    unhealthy_threshold = 3
+  }
+
+  tags = {
+    Name = %[1]q
+  }
+}
+`, rName)
+}
+
 func testAccTargetGroupConfig_protocolTLS(rName string) string {
 	return fmt.Sprintf(`
 resource "aws_vpc" "test" {

website/docs/r/lb_target_group.html.markdown

@@ -94,6 +94,7 @@ The following arguments are supported:
   Network Load Balancers do not support the `lambda` target type.
 
   Application Load Balancers do not support the `alb` target type.
+* `ip_address_type` (Optional, forces new resource) The type of IP addresses used by the target group, only supported when target type is set to `ip`. Possible values are `ipv4` or `ipv6`.
 * `vpc_id` - (Optional, Forces new resource) Identifier of the VPC in which to create the target group. Required when `target_type` is `instance`, `ip` or `alb`. Does not apply when `target_type` is `lambda`.
 
 ### health_check