azurerm_kubernetes_cluster - mark dns_zone_id optional

internal/services/containers/kubernetes_cluster_other_resource_test.go

@@ -747,6 +747,13 @@ func TestAccKubernetesCluster_webAppRouting(t *testing.T) {
 			),
 		},
 		data.ImportStep(),
+		{
+			Config: r.webAppRoutingWithDnsZone(data),
+			Check: acceptance.ComposeTestCheckFunc(
+				check.That(data.ResourceName).ExistsInAzure(r),
+			),
+		},
+		data.ImportStep(),
 	})
 }
 
@@ -2256,7 +2263,7 @@ resource "azurerm_kubernetes_cluster" "test" {
 `, data.RandomInteger, data.Locations.Primary, data.RandomInteger, data.RandomInteger, data.RandomInteger)
 }
 
-func (KubernetesClusterResource) webAppRouting(data acceptance.TestData) string {
+func (KubernetesClusterResource) webAppRoutingWithDnsZone(data acceptance.TestData) string {
 	return fmt.Sprintf(`
 provider "azurerm" {
   features {}
@@ -2295,6 +2302,45 @@ resource "azurerm_kubernetes_cluster" "test" {
  `, data.RandomInteger, data.Locations.Primary, data.RandomInteger, data.RandomInteger, data.RandomInteger)
 }
 
+func (KubernetesClusterResource) webAppRouting(data acceptance.TestData) string {
+	return fmt.Sprintf(`
+provider "azurerm" {
+  features {}
+}
+
+resource "azurerm_resource_group" "test" {
+  name     = "acctestRG-aks-%d"
+  location = "%s"
+}
+
+resource "azurerm_dns_zone" "test" {
+  name                = "acctestzone%d.com"
+  resource_group_name = azurerm_resource_group.test.name
+}
+
+resource "azurerm_kubernetes_cluster" "test" {
+  name                = "acctestaks%d"
+  location            = azurerm_resource_group.test.location
+  resource_group_name = azurerm_resource_group.test.name
+  dns_prefix          = "acctestaks%d"
+
+  default_node_pool {
+    name       = "default"
+    node_count = 1
+    vm_size    = "Standard_DS2_v2"
+  }
+
+  identity {
+    type = "SystemAssigned"
+  }
+
+  web_app_routing {
+    dns_zone_id = ""
+  }
+}
+ `, data.RandomInteger, data.Locations.Primary, data.RandomInteger, data.RandomInteger, data.RandomInteger)
+}
+
 func (KubernetesClusterResource) webAppRoutingDisabled(data acceptance.TestData) string {
 	return fmt.Sprintf(`
 provider "azurerm" {

internal/services/containers/kubernetes_cluster_resource.go

@@ -458,9 +458,12 @@ func resourceKubernetesCluster() *pluginsdk.Resource {
 				Elem: &pluginsdk.Resource{
 					Schema: map[string]*pluginsdk.Schema{
 						"dns_zone_id": {
-							Type:         pluginsdk.TypeString,
-							Required:     true,
-							ValidateFunc: dnsValidate.ValidateDnsZoneID,
+							Type:     pluginsdk.TypeString,
+							Required: true,
+							ValidateFunc: validation.Any(
+								dnsValidate.ValidateDnsZoneID,
+								validation.StringIsEmpty,
+							),
 						},
 					},
 				},
@@ -3705,23 +3708,29 @@ func base64IsEncoded(data string) bool {
 }
 
 func expandKubernetesClusterIngressProfile(d *pluginsdk.ResourceData, input []interface{}) *managedclusters.ManagedClusterIngressProfile {
-	if (len(input) == 0 || input[0] == nil) && d.HasChange("web_app_routing") {
+	if len(input) == 0 && d.HasChange("web_app_routing") {
 		return &managedclusters.ManagedClusterIngressProfile{
 			WebAppRouting: &managedclusters.ManagedClusterIngressProfileWebAppRouting{
 				Enabled: utils.Bool(false),
 			},
 		}
-	} else if len(input) == 0 || input[0] == nil {
+	} else if len(input) == 0 {
 		return nil
 	}
 
-	config := input[0].(map[string]interface{})
-	return &managedclusters.ManagedClusterIngressProfile{
+	out := managedclusters.ManagedClusterIngressProfile{
 		WebAppRouting: &managedclusters.ManagedClusterIngressProfileWebAppRouting{
-			Enabled:           utils.Bool(true),
-			DnsZoneResourceId: utils.String(config["dns_zone_id"].(string)),
+			Enabled: utils.Bool(true),
 		},
 	}
+	if input[0] != nil {
+		config := input[0].(map[string]interface{})
+		dnsZoneResourceId := config["dns_zone_id"].(string)
+		if dnsZoneResourceId != "" {
+			out.WebAppRouting.DnsZoneResourceId = utils.String(dnsZoneResourceId)
+		}
+	}
+	return &out
 }
 
 func flattenKubernetesClusterIngressProfile(input *managedclusters.ManagedClusterIngressProfile) []interface{} {

website/docs/r/kubernetes_cluster.html.markdown

@@ -792,7 +792,7 @@ A `sysctl_config` block supports the following:
 
 A `web_app_routing` block supports the following:
 
-* `dns_zone_id` - (Required) Specifies the ID of the DNS Zone in which DNS entries are created for applications deployed to the cluster when Web App Routing is enabled.
+* `dns_zone_id` - (Required) Specifies the ID of the DNS Zone in which DNS entries are created for applications deployed to the cluster when Web App Routing is enabled. For Bring-Your-Own DNS zones this property should be set to an empty string `""`.
 
 ---