Merge "allow live migration in case of a booted from volume instance"

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

@@ -5459,8 +5459,10 @@ class LibvirtConnTestCase(test.NoDBTestCase):
     def _mock_can_live_migrate_source(self, block_migration=False,
                                       is_shared_block_storage=False,
                                       is_shared_instance_path=False,
+                                      is_booted_from_volume=False,
                                       disk_available_mb=1024,
-                                      block_device_info=None):
+                                      block_device_info=None,
+                                      block_device_text=None):
         instance = objects.Instance(**self.test_instance)
         dest_check_data = {'filename': 'file',
                            'image_type': 'default',
@@ -5475,6 +5477,13 @@ class LibvirtConnTestCase(test.NoDBTestCase):
         self.mox.StubOutWithMock(drvr, '_check_shared_storage_test_file')
         drvr._check_shared_storage_test_file('file').AndReturn(
                 is_shared_instance_path)
+        self.mox.StubOutWithMock(drvr, "get_instance_disk_info")
+        drvr.get_instance_disk_info(instance,
+                                    block_device_info=block_device_info).\
+                                    AndReturn(block_device_text)
+        self.mox.StubOutWithMock(drvr, '_is_booted_from_volume')
+        drvr._is_booted_from_volume(instance, block_device_text).AndReturn(
+            is_booted_from_volume)
 
         return (instance, dest_check_data, drvr)
 
@@ -5549,7 +5558,6 @@ class LibvirtConnTestCase(test.NoDBTestCase):
                 block_migration=True,
                 disk_available_mb=0)
 
-        self.mox.StubOutWithMock(drvr, "get_instance_disk_info")
         drvr.get_instance_disk_info(instance,
                                     block_device_info=None).AndReturn(
                                         '[{"virt_disk_size":2}]')
@@ -5559,6 +5567,23 @@ class LibvirtConnTestCase(test.NoDBTestCase):
                           drvr.check_can_live_migrate_source,
                           self.context, instance, dest_check_data)
 
+    def test_check_can_live_migrate_source_booted_from_volume(self):
+        instance, dest_check_data, drvr = self._mock_can_live_migrate_source(
+                is_booted_from_volume=True,
+                block_device_text='[]')
+        self.mox.ReplayAll()
+        drvr.check_can_live_migrate_source(self.context, instance,
+                                           dest_check_data)
+
+    def test_check_can_live_migrate_source_booted_from_volume_with_swap(self):
+        instance, dest_check_data, drvr = self._mock_can_live_migrate_source(
+                is_booted_from_volume=True,
+                block_device_text='[{"path":"disk.swap"}]')
+        self.mox.ReplayAll()
+        self.assertRaises(exception.InvalidSharedStorage,
+                          drvr.check_can_live_migrate_source,
+                          self.context, instance, dest_check_data)
+
     def _is_shared_block_storage_test_create_mocks(self, disks):
         # Test data
         instance_xml = ("<domain type='kvm'><name>instance-0000000a</name>"

nova/virt/libvirt/driver.py

@@ -2661,6 +2661,20 @@ class LibvirtDriver(driver.ComputeDriver):
         return ((not bool(instance.get('image_ref')))
                 or 'disk' not in disk_mapping)
 
+    @staticmethod
+    def _has_local_disk(instance, disk_mapping):
+        """Determines whether the VM has a local disk
+
+        Determines whether the disk mapping indicates that the VM
+        has a local disk (e.g. ephemeral, swap disk and config-drive).
+        """
+        if disk_mapping:
+            if ('disk.local' in disk_mapping or
+                'disk.swap' in disk_mapping or
+                'disk.config' in disk_mapping):
+                return True
+        return False
+
     def _inject_data(self, instance, network_info, admin_pass, files, suffix):
         """Injects data in a disk image
 
@@ -5065,6 +5079,12 @@ class LibvirtDriver(driver.ComputeDriver):
                 self._is_shared_block_storage(instance, dest_check_data,
                                               block_device_info)})
 
+        disk_info_text = self.get_instance_disk_info(
+            instance, block_device_info=block_device_info)
+        booted_from_volume = self._is_booted_from_volume(instance,
+                                                         disk_info_text)
+        has_local_disk = self._has_local_disk(instance, disk_info_text)
+
         if dest_check_data['block_migration']:
             if (dest_check_data['is_shared_block_storage'] or
                     dest_check_data['is_shared_instance_path']):
@@ -5077,9 +5097,12 @@ class LibvirtDriver(driver.ComputeDriver):
                                     block_device_info)
 
         elif not (dest_check_data['is_shared_block_storage'] or
-                  dest_check_data['is_shared_instance_path']):
+                  dest_check_data['is_shared_instance_path'] or
+                  (booted_from_volume and not has_local_disk)):
             reason = _("Live migration can not be used "
-                       "without shared storage.")
+                       "without shared storage except "
+                       "a booted from volume VM which "
+                       "does not have a local disk.")
             raise exception.InvalidSharedStorage(reason=reason, path=source)
 
         # NOTE(mikal): include the instance directory name here because it