fixes #5758

* Add resource migration for Storage Account

* Update docs to show new behavior

* Update config name to indicate it's a prepare step

Co-authored-by: Jeffrey Cline <20408400+WodansSon@users.noreply.github.com>

azurerm/internal/services/storage/resource_arm_storage_account.go

@@ -66,7 +66,6 @@ func resourceArmStorageAccount() *schema.Resource {
 			"account_kind": {
 				Type:     schema.TypeString,
 				Optional: true,
-				ForceNew: true,
 				ValidateFunc: validation.StringInSlice([]string{
 					string(storage.Storage),
 					string(storage.BlobStorage),
@@ -541,6 +540,20 @@ func resourceArmStorageAccount() *schema.Resource {
 				},
 			},
 		},
+		CustomizeDiff: func(d *schema.ResourceDiff, v interface{}) error {
+			if d.HasChange("account_kind") {
+				accountKind, changedKind := d.GetChange("account_kind")
+
+				if accountKind != string(storage.Storage) && changedKind != string(storage.StorageV2) {
+					log.Printf("[DEBUG] recreate storage account, could't be migrated from %s to %s", accountKind, changedKind)
+					d.ForceNew("account_kind")
+				} else {
+					log.Printf("[DEBUG] storage account can be upgraded from %s to %s", accountKind, changedKind)
+				}
+			}
+
+			return nil
+		},
 	}
 }
 
@@ -787,6 +800,18 @@ func resourceArmStorageAccountUpdate(d *schema.ResourceData, meta interface{}) e
 		d.SetPartial("account_replication_type")
 	}
 
+	if d.HasChange("account_kind") {
+		opts := storage.AccountUpdateParameters{
+			Kind: storage.Kind(accountKind),
+		}
+
+		if _, err := client.Update(ctx, resourceGroupName, storageAccountName, opts); err != nil {
+			return fmt.Errorf("Error updating Azure Storage Account account_kind %q: %+v", storageAccountName, err)
+		}
+
+		d.SetPartial("access_kind")
+	}
+
 	if d.HasChange("access_tier") {
 		accessTier := d.Get("access_tier").(string)
 

azurerm/internal/services/storage/tests/resource_arm_storage_account_test.go

@@ -368,6 +368,33 @@ func TestAccAzureRMStorageAccount_storageV2WithUpdate(t *testing.T) {
 	})
 }
 
+func TestAccAzureRMStorageAccount_storageV1ToV2Update(t *testing.T) {
+	data := acceptance.BuildTestData(t, "azurerm_storage_account", "test")
+
+	resource.ParallelTest(t, resource.TestCase{
+		PreCheck:     func() { acceptance.PreCheck(t) },
+		Providers:    acceptance.SupportedProviders,
+		CheckDestroy: testCheckAzureRMStorageAccountDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccAzureRMStorageAccount_storageToV2Prep(data),
+				Check: resource.ComposeTestCheckFunc(
+					testCheckAzureRMStorageAccountExists(data.ResourceName),
+					resource.TestCheckResourceAttr(data.ResourceName, "account_kind", "Storage"),
+				),
+			},
+			data.ImportStep(),
+			{
+				Config: testAccAzureRMStorageAccount_storageToV2Update(data),
+				Check: resource.ComposeTestCheckFunc(
+					testCheckAzureRMStorageAccountExists(data.ResourceName),
+					resource.TestCheckResourceAttr(data.ResourceName, "account_kind", "StorageV2"),
+				),
+			},
+		},
+	})
+}
+
 func TestAccAzureRMStorageAccount_NonStandardCasing(t *testing.T) {
 	data := acceptance.BuildTestData(t, "azurerm_storage_account", "test")
 
@@ -1129,6 +1156,60 @@ resource "azurerm_storage_account" "test" {
 `, data.RandomInteger, data.Locations.Primary, data.RandomString)
 }
 
+func testAccAzureRMStorageAccount_storageToV2Prep(data acceptance.TestData) string {
+	return fmt.Sprintf(`
+provider "azurerm" {
+  features {}
+}
+
+resource "azurerm_resource_group" "test" {
+  name     = "acctestRG-storage-%d"
+  location = "%s"
+}
+
+resource "azurerm_storage_account" "test" {
+  name                = "unlikely23exst2acct%s"
+  resource_group_name = azurerm_resource_group.test.name
+
+  location                 = azurerm_resource_group.test.location
+  account_kind             = "Storage"
+  account_tier             = "Standard"
+  account_replication_type = "LRS"
+
+  tags = {
+    environment = "production"
+  }
+}
+`, data.RandomInteger, data.Locations.Primary, data.RandomString)
+}
+
+func testAccAzureRMStorageAccount_storageToV2Update(data acceptance.TestData) string {
+	return fmt.Sprintf(`
+provider "azurerm" {
+  features {}
+}
+
+resource "azurerm_resource_group" "test" {
+  name     = "acctestRG-storage-%d"
+  location = "%s"
+}
+
+resource "azurerm_storage_account" "test" {
+  name                = "unlikely23exst2acct%s"
+  resource_group_name = azurerm_resource_group.test.name
+
+  location                 = azurerm_resource_group.test.location
+  account_kind             = "StorageV2"
+  account_tier             = "Standard"
+  account_replication_type = "LRS"
+
+  tags = {
+    environment = "production"
+  }
+}
+`, data.RandomInteger, data.Locations.Primary, data.RandomString)
+}
+
 func testAccAzureRMStorageAccount_nonStandardCasing(data acceptance.TestData) string {
 	return fmt.Sprintf(`
 provider "azurerm" {

website/docs/r/storage_account.html.markdown

@@ -86,6 +86,8 @@ The following arguments are supported:
 
 * `account_kind` - (Optional) Defines the Kind of account. Valid options are `BlobStorage`, `BlockBlobStorage`, `FileStorage`, `Storage` and `StorageV2`. Changing this forces a new resource to be created. Defaults to `StorageV2`.
 
+-> **NOTE:** Changing the `account_kind` value from `Storage` to `StorageV2` will not trigger a force new on the storage account, it will only upgrade the existing storage account from `Storage` to `StorageV2` keeping the existing storage account in place.
+
 * `account_tier` - (Required) Defines the Tier to use for this storage account. Valid options are `Standard` and `Premium`. For `FileStorage` accounts only `Premium` is valid. Changing this forces a new resource to be created.
 
 * `account_replication_type` - (Required) Defines the type of replication to use for this storage account. Valid options are `LRS`, `GRS`, `RAGRS` and `ZRS`.