fix(instance_server): allow updating root_volume size for non l_ssd

docs/resources/instance_server.md

@@ -213,7 +213,7 @@ To retrieve more information by label please use: ```scw marketplace image get l
     - `size_in_gb` - (Required) Size of the root volume in gigabytes.
       To find the right size use [this endpoint](https://www.scaleway.com/en/developers/api/instance/#path-instances-list-all-instances) and
       check the `volumes_constraint.{min|max}_size` (in bytes) for your `commercial_type`.
-      Updates to this field will recreate a new resource.
+      Depending on `volume_type`, updates to this field may recreate a new resource.
     - `volume_type` - (Optional) Volume type of root volume, can be `b_ssd`, `l_ssd` or `sbs_volume`, default value depends on server type
     - `delete_on_termination` - (Defaults to `true`) Forces deletion of the root volume on instance termination.
     - `sbs_iops` - (Optional) Choose IOPS of your sbs volume, has to be used with `sbs_volume` for root volume type.

internal/services/instance/server.go

@@ -121,7 +121,6 @@ func ResourceServer() *schema.Resource {
 							Type:        schema.TypeInt,
 							Optional:    true,
 							Computed:    true,
-							ForceNew:    true,
 							Description: "Size of the root volume in gigabytes",
 						},
 						"volume_type": {
@@ -374,6 +373,7 @@ func ResourceServer() *schema.Resource {
 			),
 			customDiffInstanceServerType,
 			customDiffInstanceServerImage,
+			customDiffInstanceRootVolumeSize,
 		),
 	}
 }
@@ -1169,6 +1169,33 @@ func instanceServerCanMigrate(api *instanceSDK.API, server *instanceSDK.Server,
 	return nil
 }
 
+func customDiffInstanceRootVolumeSize(_ context.Context, diff *schema.ResourceDiff, meta interface{}) error {
+	if !diff.HasChange("root_volume.0.size_in_gb") || diff.Id() == "" {
+		return nil
+	}
+
+	instanceAPI, zone, id, err := NewAPIWithZoneAndID(meta, diff.Id())
+	if err != nil {
+		return err
+	}
+
+	resp, err := instanceAPI.GetServer(&instanceSDK.GetServerRequest{
+		Zone:     zone,
+		ServerID: id,
+	})
+	if err != nil {
+		return fmt.Errorf("failed to check server root volume type: %w", err)
+	}
+
+	if rootVolume, hasRootVolume := resp.Server.Volumes["0"]; hasRootVolume {
+		if rootVolume.VolumeType == instanceSDK.VolumeServerVolumeTypeLSSD {
+			return diff.ForceNew("root_volume.0.size_in_gb")
+		}
+	}
+
+	return nil
+}
+
 func customDiffInstanceServerType(_ context.Context, diff *schema.ResourceDiff, meta interface{}) error {
 	if !diff.HasChange("type") || diff.Id() == "" {
 		return nil

internal/services/instance/server_test.go

@@ -146,6 +146,9 @@ func TestAccServer_Minimal2(t *testing.T) {
 func TestAccServer_RootVolume1(t *testing.T) {
 	tt := acctest.NewTestTools(t)
 	defer tt.Cleanup()
+
+	serverID := ""
+
 	resource.ParallelTest(t, resource.TestCase{
 		PreCheck:          func() { acctest.PreCheck(t) },
 		ProviderFactories: tt.ProviderFactories,
@@ -166,6 +169,7 @@ func TestAccServer_RootVolume1(t *testing.T) {
 					isServerPresent(tt, "scaleway_instance_server.base"),
 					serverHasNewVolume(tt, "scaleway_instance_server.base"),
 					resource.TestCheckResourceAttr("scaleway_instance_server.base", "root_volume.0.size_in_gb", "10"),
+					acctest.CheckResourceIDPersisted("scaleway_instance_server.base", &serverID),
 				),
 			},
 			{
@@ -183,6 +187,7 @@ func TestAccServer_RootVolume1(t *testing.T) {
 					isServerPresent(tt, "scaleway_instance_server.base"),
 					serverHasNewVolume(tt, "scaleway_instance_server.base"),
 					resource.TestCheckResourceAttr("scaleway_instance_server.base", "root_volume.0.size_in_gb", "20"),
+					acctest.CheckResourceIDChanged("scaleway_instance_server.base", &serverID), // Server should have been re-created as l_ssd cannot be resized.
 				),
 			},
 		},
@@ -1702,6 +1707,9 @@ func TestAccServer_BlockExternal(t *testing.T) {
 func TestAccServer_BlockExternalRootVolume(t *testing.T) {
 	tt := acctest.NewTestTools(t)
 	defer tt.Cleanup()
+
+	serverID := ""
+
 	resource.ParallelTest(t, resource.TestCase{
 		PreCheck:          func() { acctest.PreCheck(t) },
 		ProviderFactories: tt.ProviderFactories,
@@ -1725,6 +1733,7 @@ func TestAccServer_BlockExternalRootVolume(t *testing.T) {
 					resource.TestCheckResourceAttr("scaleway_instance_server.main", "root_volume.0.volume_type", string(instanceSDK.VolumeVolumeTypeSbsVolume)),
 					resource.TestCheckResourceAttr("scaleway_instance_server.main", "root_volume.0.sbs_iops", "15000"),
 					resource.TestCheckResourceAttr("scaleway_instance_server.main", "root_volume.0.size_in_gb", "50"),
+					acctest.CheckResourceIDPersisted("scaleway_instance_server.main", &serverID),
 				),
 			},
 			{
@@ -1745,6 +1754,7 @@ func TestAccServer_BlockExternalRootVolume(t *testing.T) {
 					resource.TestCheckResourceAttr("scaleway_instance_server.main", "root_volume.0.volume_type", string(instanceSDK.VolumeVolumeTypeSbsVolume)),
 					resource.TestCheckResourceAttr("scaleway_instance_server.main", "root_volume.0.sbs_iops", "15000"),
 					resource.TestCheckResourceAttr("scaleway_instance_server.main", "root_volume.0.size_in_gb", "60"),
+					acctest.CheckResourceIDPersisted("scaleway_instance_server.main", &serverID),
 				),
 			},
 		},