Merge "Fix image ID in libvirt metadata when unshelving"

nova/tests/unit/virt/libvirt/test_driver.py

@@ -691,6 +691,7 @@ def _create_test_instance():
         'root_gb': 10,
         'ephemeral_gb': 20,
         'system_metadata': {
+            'image_base_image_ref': '155d900f-4e14-4e4c-a73d-069cbf4541e6',
             'image_disk_format': 'raw'
         },
         'instance_type_id': flavor.id,
@@ -2902,6 +2903,48 @@ class LibvirtConnTestCase(test.NoDBTestCase,
         self.assertEqual(meta.ports.ports[1].ips[1].ip_type, 'fixed')
         self.assertEqual(meta.ports.ports[1].ips[1].ip_version, 6)
 
+    def test_get_guest_config_meta_building_image_id(self):
+        test_instance = copy.deepcopy(self.test_instance)
+        test_instance["vm_state"] = "building"
+        drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
+        idm = drvr.get_instance_driver_metadata(
+            objects.Instance(**test_instance),
+            _fake_network_info(self))
+        meta = drvr._get_guest_config_meta(idm)
+
+        self.assertEqual("image", meta.roottype)
+        self.assertEqual("155d900f-4e14-4e4c-a73d-069cbf4541e6",
+                         meta.rootid)
+
+    def test_get_guest_config_meta_no_base_image_ref_image_id(self):
+        test_instance = copy.deepcopy(self.test_instance)
+        test_instance["system_metadata"] = {"image_disk_format": "raw"}
+        drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
+        idm = drvr.get_instance_driver_metadata(
+            objects.Instance(**test_instance),
+            _fake_network_info(self))
+        meta = drvr._get_guest_config_meta(idm)
+
+        self.assertEqual("image", meta.roottype)
+        self.assertEqual("155d900f-4e14-4e4c-a73d-069cbf4541e6",
+                         meta.rootid)
+
+    def test_get_guest_config_meta_unshelve_image_id(self):
+        test_instance = copy.deepcopy(self.test_instance)
+        test_instance["vm_state"] = "shelved_offloaded"
+        test_instance["system_metadata"]["image_base_image_ref"] = (
+            "85daefce-4e20-4d2b-a4f3-11d3765f2a8f")
+        drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
+        idm = drvr.get_instance_driver_metadata(
+            objects.Instance(**test_instance),
+            _fake_network_info(self))
+        meta = drvr._get_guest_config_meta(idm)
+
+        self.assertEqual("image", meta.roottype)
+        self.assertEqual(test_instance["system_metadata"][
+                            "image_base_image_ref"],
+                         meta.rootid)
+
     @mock.patch.object(time, "time")
     def test_get_guest_config(self, time_mock):
         """Generate a "standard" guest with minimal configuration.

nova/virt/driver.py

@@ -394,7 +394,14 @@ class ComputeDriver(object):
             flavor=flavor,
             image=image,
             root_type = 'image' if instance.image_ref else 'volume',
-            root_id = instance.image_ref,
+            # NOTE(callumdickinson): Once an image-backed instance has
+            # been shelved, instance.image_ref changes to the ID of the
+            # temporary image storing the root volume while shelved.
+            # Prefer base_image_ref from the system metadata, if available,
+            # to ensure that the ID of the original image the instance was
+            # booted from is used for the driver metadata.
+            root_id=system_meta.get('image_base_image_ref',
+                                    instance.image_ref),
             creation_time = time.time(),
             network_info=network_info
         )

releasenotes/notes/bug-2100588-fix-image-id-xml-after-unshelve-e5f6116043ba1c41.yaml

@@ -0,0 +1,12 @@
+---
+fixes:
+  - |
+    When an instance booted from local storage is unshelved,
+    the image ID published to the libvirt domain metadata was
+    the ID for the temporary Glance image generated to store
+    the instance state, instead of the original image as intended.
+    Since the temporary image is removed after the instance is
+    unshelved, this results in an invalid image ID being stored
+    in the libvirt domain metadata. This issue has now been fixed.
+    Affected instances will need to be shutdown, restarted, cold
+    migrated or shelved-and-unshelved to update the metadata.