Merge "Revert "libvirt: support live migrate of instances with conf drives""

3 files changed, 34 insertions, 26 deletions

diff --git a/nova/exception.py b/nova/exception.py
index b4b471e864..efc5492529 100644
--- a/nova/exception.py
+++ b/nova/exception.py
@@ -1650,6 +1650,12 @@ class InvalidWatchdogAction(Invalid):
     msg_fmt = _("Provided watchdog action (%(action)s) is not supported.")
 
 
+class NoLiveMigrationForConfigDriveInLibVirt(NovaException):
+    msg_fmt = _("Live migration of instances with config drives is not "
+                "supported in libvirt unless libvirt instance path and "
+                "drive data is shared across compute nodes.")
+
+
 class LiveMigrationWithOldNovaNotSafe(NovaException):
     msg_fmt = _("Host %(server)s is running an old version of Nova, "
                 "live migrations involving that version may cause data loss. "
diff --git a/nova/tests/virt/libvirt/test_driver.py b/nova/tests/virt/libvirt/test_driver.py
index b7e914e2ab..0dd21bd86b 100644
--- a/nova/tests/virt/libvirt/test_driver.py
+++ b/nova/tests/virt/libvirt/test_driver.py
@@ -5753,6 +5753,26 @@ class LibvirtConnTestCase(test.TestCase):
                                                 'vnc': '127.0.0.1'}}
         self.assertEqual(result, target_res)
 
+    def test_pre_live_migration_block_with_config_drive_mocked(self):
+        # Creating testdata
+        vol = {'block_device_mapping': [
+                  {'connection_info': 'dummy', 'mount_device': '/dev/sda'},
+                  {'connection_info': 'dummy', 'mount_device': '/dev/sdb'}]}
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
+
+        def fake_true(*args, **kwargs):
+            return True
+
+        self.stubs.Set(configdrive, 'required_by', fake_true)
+
+        inst_ref = {'id': 'foo'}
+        c = context.get_admin_context()
+
+        self.assertRaises(exception.NoLiveMigrationForConfigDriveInLibVirt,
+                          conn.pre_live_migration, c, inst_ref, vol, None,
+                          None, {'is_shared_instance_path': False,
+                                 'is_shared_block_storage': False})
+
     def test_pre_live_migration_vol_backed_works_correctly_mocked(self):
         # Creating testdata, using temp dir.
         with utils.tempdir() as tmpdir:
@@ -12030,13 +12050,6 @@ class LibvirtDriverTestCase(test.TestCase):
         cdb.make_drive(mox.Regex(configdrive_path))
         cdb.__exit__(mox.IgnoreArg(), mox.IgnoreArg(), mox.IgnoreArg()
                         ).AndReturn(None)
-
-        imagebackend.Backend.image(instance, 'disk.config.rescue', 'raw'
-                                   ).AndReturn(fake_imagebackend.Raw())
-        imagebackend.Image.cache(fetch_func=mox.IgnoreArg(),
-                                 context=mox.IgnoreArg(),
-                                 filename='disk.config.rescue')
-
         image_meta = {'id': 'fake', 'name': 'fake'}
         self.libvirtconnection._get_guest_xml(mox.IgnoreArg(), instance,
                                 network_info, mox.IgnoreArg(),
diff --git a/nova/virt/libvirt/driver.py b/nova/virt/libvirt/driver.py
index f587bb8147..6b1c1b7a98 100644
--- a/nova/virt/libvirt/driver.py
+++ b/nova/virt/libvirt/driver.py
@@ -3083,16 +3083,6 @@ class LibvirtDriver(driver.ComputeDriver):
                                       'with error: %s'),
                                   e, instance=instance)
 
-                def dummy_fetch_func(target, *args, **kwargs):
-                    # NOTE(sileht): this is never called because the
-                    # the target have already been created by
-                    # cdb.make_drive call
-                    pass
-
-                raw('disk.config').cache(fetch_func=dummy_fetch_func,
-                                         context=context,
-                                         filename='disk.config' + suffix)
-
         # File injection only if needed
         elif inject_files and CONF.libvirt.inject_partition != -2:
             if booted_from_volume:
@@ -3478,19 +3468,11 @@ class LibvirtDriver(driver.ComputeDriver):
                         block_device.prepend_dev(diskswap.target_dev))
 
             if 'disk.config' in disk_mapping:
-                # NOTE(sileht): a configdrive is a raw image
-                # it works well with rbd, lvm and raw images_type
-                # but we must force to raw image_type if the desired
-                # images_type is qcow2
-                if CONF.libvirt.images_type not in ['rbd', 'lvm']:
-                    image_type = "raw"
-                else:
-                    image_type = None
                 diskconfig = self._get_guest_disk_config(instance,
                                                          'disk.config',
                                                          disk_mapping,
                                                          inst_type,
-                                                         image_type)
+                                                         'raw')
                 devices.append(diskconfig)
 
         for vol in block_device.get_bdms_to_connect(block_device_mapping,
@@ -5440,6 +5422,13 @@ class LibvirtDriver(driver.ComputeDriver):
             is_block_migration = migrate_data.get('block_migration', True)
             instance_relative_path = migrate_data.get('instance_relative_path')
 
+        if not (is_shared_instance_path and is_shared_block_storage):
+            # NOTE(mikal): live migration of instances using config drive is
+            # not supported because of a bug in libvirt (read only devices
+            # are not copied by libvirt). See bug/1246201
+            if configdrive.required_by(instance):
+                raise exception.NoLiveMigrationForConfigDriveInLibVirt()
+
         if not is_shared_instance_path:
             # NOTE(mikal): this doesn't use libvirt_utils.get_instance_path
             # because we are ensuring that the same instance directory name