azurerm_lb: Support for adding/replacing frontend_ip_configuration with availability_zone

internal/services/loadbalancer/loadbalancer_resource.go

@@ -1,6 +1,7 @@
 package loadbalancer
 
 import (
+	"context"
 	"fmt"
 	"log"
 	"strings"
@@ -79,7 +80,6 @@ func resourceArmLoadBalancer() *pluginsdk.Resource {
 							Optional: true,
 							//Default:  "Zone-Redundant",
 							Computed: true,
-							ForceNew: true,
 							ValidateFunc: validation.StringInSlice([]string{
 								"No-Zone",
 								"1",
@@ -177,7 +177,6 @@ func resourceArmLoadBalancer() *pluginsdk.Resource {
 							Type:       pluginsdk.TypeList,
 							Optional:   true,
 							Computed:   true,
-							ForceNew:   true,
 							Deprecated: "This property has been deprecated in favour of `availability_zone` due to a breaking behavioural change in Azure: https://azure.microsoft.com/en-us/updates/zone-behavior-change/",
 							MaxItems:   1,
 							Elem: &pluginsdk.Schema{
@@ -208,6 +207,25 @@ func resourceArmLoadBalancer() *pluginsdk.Resource {
 
 			"tags": tags.Schema(),
 		},
+
+		CustomizeDiff: pluginsdk.CustomizeDiffShim(func(ctx context.Context, d *pluginsdk.ResourceDiff, v interface{}) error {
+			if ok := d.HasChange("frontend_ip_configuration"); ok {
+				configs := d.Get("frontend_ip_configuration").([]interface{})
+
+				for index := range configs {
+					if d.HasChange(fmt.Sprintf("frontend_ip_configuration.%d.availability_zone", index)) && !d.HasChange(fmt.Sprintf("frontend_ip_configuration.%d.name", index)) {
+						return fmt.Errorf("in place change of the `frontend_ip_configuration.%[1]d.availability_zone` is not allowed. It is allowed to do this while also changing `frontend_ip_configuration.%[1]d.name`", index)
+					}
+
+					// TODO - Remove in 3.0
+					if d.HasChange(fmt.Sprintf("frontend_ip_configuration.%d.zones", index)) && !d.HasChange(fmt.Sprintf("frontend_ip_configuration.%d.name", index)) {
+						return fmt.Errorf("in place change of the `frontend_ip_configuration.%[1]d.zones` is not allowed. It is allowed to do this while also changing `frontend_ip_configuration.%[1]d.name`", index)
+					}
+				}
+			}
+
+			return nil
+		}),
 	}
 }
 

internal/services/loadbalancer/loadbalancer_resource_test.go

@@ -165,6 +165,42 @@ func TestAccAzureRMLoadBalancer_privateIP(t *testing.T) {
 	})
 }
 
+func TestAccAzureRMLoadBalancer_updateFrontEndConfigsWithZone(t *testing.T) {
+	data := acceptance.BuildTestData(t, "azurerm_lb", "test")
+	r := LoadBalancer{}
+
+	data.ResourceTest(t, r, []acceptance.TestStep{
+		{
+			Config: r.availability_zone_update1(data, "Zone-Redundant"),
+			Check: acceptance.ComposeTestCheckFunc(
+				check.That(data.ResourceName).ExistsInAzure(r),
+			),
+		},
+		data.ImportStep(),
+		{
+			Config: r.availability_zone_update1(data, "No-Zone"),
+			Check: acceptance.ComposeTestCheckFunc(
+				check.That(data.ResourceName).ExistsInAzure(r),
+			),
+		},
+		data.ImportStep(),
+		{
+			Config: r.availability_zone_update1(data, "Zone-Redundant"),
+			Check: acceptance.ComposeTestCheckFunc(
+				check.That(data.ResourceName).ExistsInAzure(r),
+			),
+		},
+		data.ImportStep(),
+		{
+			Config: r.availability_zone_update2(data, "Zone-Redundant"),
+			Check: acceptance.ComposeTestCheckFunc(
+				check.That(data.ResourceName).ExistsInAzure(r),
+			),
+		},
+		data.ImportStep(),
+	})
+}
+
 func TestAccAzureRMLoadBalancer_ZoneRedundant(t *testing.T) {
 	data := acceptance.BuildTestData(t, "azurerm_lb", "test")
 	r := LoadBalancer{}
@@ -585,3 +621,98 @@ resource "azurerm_lb" "test" {
 }
 `, data.RandomInteger, data.Locations.Primary, data.RandomInteger, data.RandomInteger, data.RandomInteger, zone)
 }
+
+func (r LoadBalancer) availability_zone_update1(data acceptance.TestData, zone string) string {
+	return fmt.Sprintf(`
+provider "azurerm" {
+  features {}
+}
+
+resource "azurerm_resource_group" "test" {
+  name     = "acctestRG-lb-%[1]d"
+  location = "%[2]s"
+}
+
+resource "azurerm_virtual_network" "test" {
+  name                = "acctvn-%[1]d"
+  address_space       = ["10.0.0.0/16"]
+  location            = azurerm_resource_group.test.location
+  resource_group_name = azurerm_resource_group.test.name
+}
+
+resource "azurerm_subnet" "test" {
+  name                 = "acctsub-%[1]d"
+  resource_group_name  = azurerm_resource_group.test.name
+  virtual_network_name = azurerm_virtual_network.test.name
+  address_prefix       = "10.0.2.0/24"
+}
+
+resource "azurerm_lb" "test" {
+  name                = "acctestlb-%[1]d"
+  resource_group_name = azurerm_resource_group.test.name
+  location            = azurerm_resource_group.test.location
+  sku                 = "Standard"
+
+  frontend_ip_configuration {
+    name                          = "Internal-%[3]s"
+    private_ip_address_allocation = "Static"
+    private_ip_address_version    = "IPv4"
+    private_ip_address            = "10.0.2.7"
+    subnet_id                     = azurerm_subnet.test.id
+    availability_zone             = "%[3]s"
+  }
+}
+`, data.RandomInteger, data.Locations.Primary, zone)
+}
+
+func (r LoadBalancer) availability_zone_update2(data acceptance.TestData, zone string) string {
+	return fmt.Sprintf(`
+provider "azurerm" {
+  features {}
+}
+
+resource "azurerm_resource_group" "test" {
+  name     = "acctestRG-lb-%[1]d"
+  location = "%[2]s"
+}
+
+resource "azurerm_virtual_network" "test" {
+  name                = "acctvn-%[1]d"
+  address_space       = ["10.0.0.0/16"]
+  location            = azurerm_resource_group.test.location
+  resource_group_name = azurerm_resource_group.test.name
+}
+
+resource "azurerm_subnet" "test" {
+  name                 = "acctsub-%[1]d"
+  resource_group_name  = azurerm_resource_group.test.name
+  virtual_network_name = azurerm_virtual_network.test.name
+  address_prefix       = "10.0.2.0/24"
+}
+
+resource "azurerm_lb" "test" {
+  name                = "acctestlb-%[1]d"
+  resource_group_name = azurerm_resource_group.test.name
+  location            = azurerm_resource_group.test.location
+  sku                 = "Standard"
+
+  frontend_ip_configuration {
+    name                          = "Internal-%[3]s"
+    private_ip_address_allocation = "Static"
+    private_ip_address_version    = "IPv4"
+    private_ip_address            = "10.0.2.7"
+    subnet_id                     = azurerm_subnet.test.id
+    availability_zone             = "%[3]s"
+  }
+
+  frontend_ip_configuration {
+    name                          = "Internal2-%[3]s"
+    private_ip_address_allocation = "Static"
+    private_ip_address_version    = "IPv4"
+    private_ip_address            = "10.0.2.8"
+    subnet_id                     = azurerm_subnet.test.id
+    availability_zone             = "%[3]s"
+  }
+}
+`, data.RandomInteger, data.Locations.Primary, zone)
+}

website/docs/r/lb.html.markdown

@@ -52,7 +52,7 @@ The following arguments are supported:
 `frontend_ip_configuration` supports the following:
 
 * `name` - (Required) Specifies the name of the frontend ip configuration.
-* `availability_zone` - (Optional) A list of Availability Zones which the Load Balancer's IP Addresses should be created in. Possible values are `Zone-Redundant`, `1`, `2`, `3`, and `No-Zone`. Defaults to `Zone-Redundant`.
+* `availability_zone` - (Optional) A list of Availability Zones which the Load Balancer's IP Addresses should be created in. Possible values are `Zone-Redundant`, `1`, `2`, `3`, and `No-Zone`. Availability Zone can only be updated whenever the name of the front end ip configuration changes. Defaults to `Zone-Redundant`. 
  `No-Zones` - A `non-zonal` resource will be created and the resource will not be replicated or distributed to any Availability Zones.
 
  `1`, `2` or `3` (e.g. single Availability Zone) - A `zonal` resource will be created and will be replicate or distribute to a single specific Availability Zone.