Fix breaking change of requiring private_dns_zone_id in azurerm_postgresql_flexible_server

azurerm/internal/services/postgres/postgresql_flexible_server_resource.go

@@ -15,6 +15,7 @@ import (
 	networkValidate "github.com/terraform-providers/terraform-provider-azurerm/azurerm/internal/services/network/validate"
 	"github.com/terraform-providers/terraform-provider-azurerm/azurerm/internal/services/postgres/parse"
 	"github.com/terraform-providers/terraform-provider-azurerm/azurerm/internal/services/postgres/validate"
+	privateDnsValidate "github.com/terraform-providers/terraform-provider-azurerm/azurerm/internal/services/privatedns/validate"
 	"github.com/terraform-providers/terraform-provider-azurerm/azurerm/internal/tags"
 	"github.com/terraform-providers/terraform-provider-azurerm/azurerm/internal/tf/pluginsdk"
 	"github.com/terraform-providers/terraform-provider-azurerm/azurerm/internal/tf/validation"
@@ -118,6 +119,17 @@ func resourcePostgresqlFlexibleServer() *pluginsdk.Resource {
 				ValidateFunc: networkValidate.SubnetID,
 			},
 
+			"private_dns_zone_id": {
+				Type:     pluginsdk.TypeString,
+				Optional: true,
+				Computed: true,
+				// This is `computed`, because there is a breaking change to require this field when setting vnet.
+				// For existing fs who don't want to be recreated, they could contact service team to manually migrate to the private dns zone
+				// We need to ignore the diff when remote is set private dns zone
+				ForceNew:     true,
+				ValidateFunc: privateDnsValidate.PrivateDnsZoneID,
+			},
+
 			"point_in_time_restore_time_in_utc": {
 				Type:         pluginsdk.TypeString,
 				Optional:     true,
@@ -350,6 +362,7 @@ func resourcePostgresqlFlexibleServerRead(d *pluginsdk.ResourceData, meta interf
 		if network := props.Network; network != nil {
 			d.Set("public_network_access_enabled", network.PublicNetworkAccess == postgresqlflexibleservers.ServerPublicNetworkAccessStateEnabled)
 			d.Set("delegated_subnet_id", network.DelegatedSubnetResourceID)
+			d.Set("private_dns_zone_id", network.PrivateDNSZoneArmResourceID)
 		}
 
 		if err := d.Set("maintenance_window", flattenArmServerMaintenanceWindow(props.MaintenanceWindow)); err != nil {
@@ -458,6 +471,10 @@ func expandArmServerNetwork(d *pluginsdk.ResourceData) *postgresqlflexibleserver
 		network.DelegatedSubnetResourceID = utils.String(v.(string))
 	}
 
+	if v, ok := d.GetOk("private_dns_zone_id"); ok {
+		network.PrivateDNSZoneArmResourceID = utils.String(v.(string))
+	}
+
 	return &network
 }
 

azurerm/internal/services/postgres/postgresql_flexible_server_resource_test.go

@@ -291,6 +291,18 @@ resource "azurerm_subnet" "test" {
   }
 }
 
+resource "azurerm_private_dns_zone" "test" {
+  name                = "acc%[2]d.postgres.database.azure.com"
+  resource_group_name = azurerm_resource_group.test.name
+}
+
+resource "azurerm_private_dns_zone_virtual_network_link" "test" {
+  name                  = "acctestVnetZone%[2]d.com"
+  private_dns_zone_name = azurerm_private_dns_zone.test.name
+  virtual_network_id    = azurerm_virtual_network.test.id
+  resource_group_name   = azurerm_resource_group.test.name
+}
+
 resource "azurerm_postgresql_flexible_server" "test" {
   name                   = "acctest-fs-%[2]d"
   resource_group_name    = azurerm_resource_group.test.name
@@ -302,6 +314,7 @@ resource "azurerm_postgresql_flexible_server" "test" {
   backup_retention_days  = 7
   storage_mb             = 32768
   delegated_subnet_id    = azurerm_subnet.test.id
+  private_dns_zone_id    = azurerm_private_dns_zone.test.id
   sku_name               = "GP_Standard_D2s_v3"
 
   maintenance_window {
@@ -313,6 +326,8 @@ resource "azurerm_postgresql_flexible_server" "test" {
   tags = {
     ENV = "Test"
   }
+
+  depends_on = [azurerm_private_dns_zone_virtual_network_link.test]
 }
 `, r.template(data), data.RandomInteger)
 }
@@ -345,6 +360,18 @@ resource "azurerm_subnet" "test" {
   }
 }
 
+resource "azurerm_private_dns_zone" "test" {
+  name                = "acc%[2]d.postgres.database.azure.com"
+  resource_group_name = azurerm_resource_group.test.name
+}
+
+resource "azurerm_private_dns_zone_virtual_network_link" "test" {
+  name                  = "acctestVnetZone%[2]d.com"
+  private_dns_zone_name = azurerm_private_dns_zone.test.name
+  virtual_network_id    = azurerm_virtual_network.test.id
+  resource_group_name   = azurerm_resource_group.test.name
+}
+
 resource "azurerm_postgresql_flexible_server" "test" {
   name                   = "acctest-fs-%[2]d"
   resource_group_name    = azurerm_resource_group.test.name
@@ -356,6 +383,7 @@ resource "azurerm_postgresql_flexible_server" "test" {
   backup_retention_days  = 10
   storage_mb             = 65536
   delegated_subnet_id    = azurerm_subnet.test.id
+  private_dns_zone_id    = azurerm_private_dns_zone.test.id
   sku_name               = "GP_Standard_D2s_v3"
 
   maintenance_window {
@@ -367,6 +395,8 @@ resource "azurerm_postgresql_flexible_server" "test" {
   tags = {
     ENV = "Stage"
   }
+
+  depends_on = [azurerm_private_dns_zone_virtual_network_link.test]
 }
 `, r.template(data), data.RandomInteger)
 }

website/docs/r/postgresql_flexible_server.html.markdown

@@ -45,19 +45,33 @@ resource "azurerm_subnet" "example" {
     }
   }
 }
+resource "azurerm_private_dns_zone" "example" {
+  name                = "example.postgres.database.azure.com"
+  resource_group_name = azurerm_resource_group.example.name
+}
+
+resource "azurerm_private_dns_zone_virtual_network_link" "example" {
+  name                  = "exampleVnetZone.com"
+  private_dns_zone_name = azurerm_private_dns_zone.example.name
+  virtual_network_id    = azurerm_virtual_network.example.id
+  resource_group_name   = azurerm_resource_group.example.name
+}
 
 resource "azurerm_postgresql_flexible_server" "example" {
   name                   = "example-psqlflexibleserver"
   resource_group_name    = azurerm_resource_group.example.name
   location               = azurerm_resource_group.example.location
   version                = "12"
   delegated_subnet_id    = azurerm_subnet.example.id
+  private_dns_zone_id    = azurerm_private_dns_zone.example.id
   administrator_login    = "psqladminun"
   administrator_password = "H@Sh1CoR3!"
 
   storage_mb = 32768
 
-  sku_name = "GP_Standard_D4s_v3"
+  sku_name   = "GP_Standard_D4s_v3"
+  depends_on = [azurerm_private_dns_zone_virtual_network_link.example]
+
 }
 ```
 
@@ -83,6 +97,10 @@ The following arguments are supported:
 
 * `delegated_subnet_id` - (Optional) The ID of the virtual network subnet to create the PostgreSQL Flexible Server. The provided subnet should not have any other resource deployed in it and this subnet will be delegated to the PostgreSQL Flexible Server, if not already delegated. Changing this forces a new PostgreSQL Flexible Server to be created.
 
+* `private_dns_zone_id` - (Optional) The ID of the private dns zone to create the PostgreSQL Flexible Server. Changing this forces a new PostgreSQL Flexible Server to be created.
+
+~> **NOTE:** There will be a breaking change from upstream service at 15th July 2021, the `private_dns_zone_id` will be required when setting a `delegated_subnet_id`. For existing flexible servers who don't want to be recreated, you need to provide the `private_dns_zone_id` to the service team to manually migrate to the specified private dns zone. The `azurerm_private_dns_zone` should end with suffix `.postgres.database.azure.com`.
+
 * `maintenance_window` - (Optional) A `maintenance_window` block as defined below.
 
 * `point_in_time_restore_time_in_utc` - (Optional) The point in time to restore from `creation_source_server_id` when `create_mode` is `PointInTimeRestore`. Changing this forces a new PostgreSQL Flexible Server to be created.