From 2faf17995dd9daa6f0b91e44be43264e447c678d Mon Sep 17 00:00:00 2001 From: Lee Yarwood Date: Wed, 5 Aug 2020 23:00:06 +0100 Subject: [PATCH] libvirt: Provide VIR_MIGRATE_PARAM_PERSIST_XML during live migration The VIR_MIGRATE_PARAM_PERSIST_XML parameter was introduced in libvirt v1.3.4 and is used to provide the new persistent configuration for the destination during a live migration: https://libvirt.org/html/libvirt-libvirt-domain.html#VIR_MIGRATE_PARAM_PERSIST_XML Without this parameter the persistent configuration on the destination will be the same as the original persistent configuration on the source when the VIR_MIGRATE_PERSIST_DEST flag is provided. As Nova does not currently provide the VIR_MIGRATE_PARAM_PERSIST_XML param but does provide the VIR_MIGRATE_PERSIST_DEST flag this means that a soft reboot by Nova of the instance after a live migration can revert the domain back to the original persistent configuration from the source. Note that this is only possible in Nova as a soft reboot actually results in the virDomainShutdown and virDomainLaunch libvirt APIs being called that recreate the domain using the persistent configuration. virDomainReboot does not result in this but is not called at this time. The impact of this on the instance after the soft reboot is pretty severe, host devices referenced in the original persistent configuration on the source may not exist or could even be used by other users on the destination. CPU and NUMA affinity could also differ drastically between the two hosts resulting in the instance being unable to start etc. As MIN_LIBVIRT_VERSION is now > v1.3.4 this change simply includes the VIR_MIGRATE_PARAM_PERSIST_XML param using the same updated XML for the destination as is already provided to VIR_MIGRATE_PARAM_DEST_XML. Conflicts: nova/tests/unit/virt/libvirt/test_driver.py nova/virt/libvirt/driver.py NOTE(melwitt): Conflicts in driver.py are because changes: I6ac601e633ab2b0a67b4802ff880865255188a93 (libvirt: Provide VGPU inventory for a single GPU type) I947bf0ad34a48e9182a3dc016f47f0c9f71c9d7b ([libvirt] Allow multiple volume attachments) Ibfa64f18bbd2fb70db7791330ed1a64fe61c1355 (libvirt: QEMU native LUKS decryption for encrypted volumes) If2035cac931c42c440d61ba97ebc7e9e92141a28 (libvirt: Rework 'EBUSY' (SIGKILL) error handling code path) Ibf210dd27972fed2651d6c9bd73a0bcf352c8bab (libvirt: create vGPU for instance) are not in Pike. Conflict in test_driver.py is because the Pike backport of change I9b545ca8aa6dd7b41ddea2d333190c9fbed19bc1 explicitly asserts byte string destination_xml in _test_live_migration_block_migration_flags and the change is not in Queens where this is being backported from. Co-authored-by: Tadayoshi Hosoya Closes-Bug: #1890501 Change-Id: Ia3f1d8e83cbc574ce5cb440032e12bbcb1e10e98 (cherry picked from commit 1bb8ee95d4c3ddc3f607ac57526b75af1b7fbcff) (cherry picked from commit bbf9d1de06e9991acd968fceee899a8df3776d60) (cherry picked from commit 6a07edb4b29d8bfb5c86ed14263f7cd7525958c1) (cherry picked from commit b9ea91d17703f5b324a50727b6503ace0f4e95eb) (cherry picked from commit c438fd9a0eb1903306a53ab44e3ae80660d8a429) (cherry picked from commit a721ca5f510ce3c8ef24f22dac9e475b3d7651db) --- nova/tests/unit/virt/libvirt/test_driver.py | 88 +++++++++++++++++++-- nova/virt/libvirt/driver.py | 11 +++ 2 files changed, 93 insertions(+), 6 deletions(-) diff --git a/nova/tests/unit/virt/libvirt/test_driver.py b/nova/tests/unit/virt/libvirt/test_driver.py index f5595e8eab19..8ba4bc46b00c 100755 --- a/nova/tests/unit/virt/libvirt/test_driver.py +++ b/nova/tests/unit/virt/libvirt/test_driver.py @@ -8536,6 +8536,76 @@ class LibvirtConnTestCase(test.NoDBTestCase, 'instance', data, block_device_info=bdi)) self.assertEqual(0, mock_get_instance_disk_info.call_count) + @mock.patch.object(fakelibvirt.virDomain, "migrateToURI3") + @mock.patch('nova.virt.libvirt.migration.get_updated_guest_xml') + @mock.patch.object(fakelibvirt.Connection, 'getLibVersion') + def test_live_migration_persistent_xml( + self, mock_get_version, mock_get_updated_xml, mock_migrateToURI3): + """Assert that persistent_xml only provided when libvirt is >= v1.3.4 + """ + drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False) + instance = self.test_instance + dest = '127.0.0.1' + block_migration = False + migrate_data = objects.LibvirtLiveMigrateData( + graphics_listen_addr_vnc='10.0.0.1', + graphics_listen_addr_spice='10.0.0.2', + serial_listen_addr='127.0.0.1', + target_connect_addr='127.0.0.1', + bdms=[], + block_migration=block_migration) + guest = libvirt_guest.Guest(fakelibvirt.virDomain) + device_names = ['vda'] + + mock_get_updated_xml.return_value = mock.sentinel.dest_xml + + # persistent_xml was introduced in v1.3.4 so provide v1.3.3 + v1_3_3 = versionutils.convert_version_to_int((1, 3, 3)) + mock_get_version.return_value = v1_3_3 + + drvr._live_migration_operation( + self.context, instance, dest, block_migration, migrate_data, + guest, device_names) + + expected_uri = drvr._live_migration_uri(dest) + expected_flags = 0 + expected_params = { + 'bandwidth': 0, + 'destination_xml': mock.sentinel.dest_xml, + 'migrate_disks': device_names, + 'migrate_uri': 'tcp://127.0.0.1' + } + + # Assert that migrateToURI3 is called without the persistent_xml param + mock_get_version.assert_called() + mock_migrateToURI3.assert_called_once_with( + expected_uri, params=expected_params, flags=expected_flags) + + # reset mocks and try again with v1.3.4 + mock_get_version.reset_mock() + mock_migrateToURI3.reset_mock() + + # persistent_xml was introduced in v1.3.4 so provide it this time + v1_3_4 = versionutils.convert_version_to_int((1, 3, 4)) + mock_get_version.return_value = v1_3_4 + + drvr._live_migration_operation( + self.context, instance, dest, + block_migration, migrate_data, guest, device_names) + + expected_params = { + 'bandwidth': 0, + 'destination_xml': mock.sentinel.dest_xml, + 'persistent_xml': mock.sentinel.dest_xml, + 'migrate_disks': device_names, + 'migrate_uri': 'tcp://127.0.0.1' + } + + # Assert that migrateToURI3 is called with the persistent_xml param + mock_get_version.assert_called() + mock_migrateToURI3.assert_called_once_with( + expected_uri, params=expected_params, flags=expected_flags) + def test_live_migration_update_graphics_xml(self): self.compute = manager.ComputeManager() instance_dict = dict(self.test_instance) @@ -9059,19 +9129,21 @@ class LibvirtConnTestCase(test.NoDBTestCase, @mock.patch.object(host.Host, 'has_min_version', return_value=True) @mock.patch.object(fakelibvirt.virDomain, "migrateToURI3") - @mock.patch('nova.virt.libvirt.migration.get_updated_guest_xml', - return_value='') + @mock.patch('nova.virt.libvirt.migration.get_updated_guest_xml') @mock.patch('nova.virt.libvirt.guest.Guest.get_xml_desc', return_value='') def test_live_migration_uses_migrateToURI3( self, mock_old_xml, mock_new_xml, mock_migrateToURI3, mock_min_version): + + mock_new_xml.return_value = mock.sentinel.new_xml # Preparing mocks disk_paths = ['vda', 'vdb'] params = { 'migrate_disks': ['vda', 'vdb'], 'bandwidth': CONF.libvirt.live_migration_bandwidth, - 'destination_xml': '', + 'destination_xml': mock.sentinel.new_xml, + 'persistent_xml': mock.sentinel.new_xml, } mock_migrateToURI3.side_effect = fakelibvirt.libvirtError("ERR") @@ -9126,6 +9198,7 @@ class LibvirtConnTestCase(test.NoDBTestCase, 'migrate_disks': device_names, 'bandwidth': CONF.libvirt.live_migration_bandwidth, 'destination_xml': b'', + 'persistent_xml': b'', } mock_migrateToURI3.assert_called_once_with( drvr._live_migration_uri('dest'), params=params, @@ -9154,18 +9227,21 @@ class LibvirtConnTestCase(test.NoDBTestCase, @mock.patch.object(host.Host, 'has_min_version', return_value=True) @mock.patch.object(fakelibvirt.virDomain, "migrateToURI3") - @mock.patch('nova.virt.libvirt.migration.get_updated_guest_xml', - return_value='') + @mock.patch('nova.virt.libvirt.migration.get_updated_guest_xml') @mock.patch('nova.virt.libvirt.guest.Guest.get_xml_desc', return_value='') def test_block_live_migration_tunnelled_migrateToURI3( self, mock_old_xml, mock_new_xml, mock_migrateToURI3, mock_min_version): self.flags(live_migration_tunnelled=True, group='libvirt') + + mock_new_xml.return_value = mock.sentinel.new_xml + # Preparing mocks disk_paths = [] params = { 'bandwidth': CONF.libvirt.live_migration_bandwidth, - 'destination_xml': '', + 'destination_xml': mock.sentinel.new_xml, + 'persistent_xml': mock.sentinel.new_xml, } # Start test migrate_data = objects.LibvirtLiveMigrateData( diff --git a/nova/virt/libvirt/driver.py b/nova/virt/libvirt/driver.py index c616406088ee..b063a6a55770 100644 --- a/nova/virt/libvirt/driver.py +++ b/nova/virt/libvirt/driver.py @@ -302,6 +302,11 @@ PERF_EVENTS_CPU_FLAG_MAPPING = {'cmt': 'cmt', 'mbmt': 'mbm_total', } +# libvirt >= v1.3.4 introduced VIR_MIGRATE_PARAM_PERSIST_XML that needs to be +# provided when the VIR_MIGRATE_PERSIST_DEST flag is used to ensure the updated +# domain XML is persisted on the destination. +MIN_LIBVIRT_MIGRATE_PARAM_PERSIST_XML = (1, 3, 4) + class LibvirtDriver(driver.ComputeDriver): capabilities = { @@ -6519,6 +6524,12 @@ class LibvirtDriver(driver.ComputeDriver): libvirt.VIR_MIGRATE_TUNNELLED != 0): params.pop('migrate_disks') + # NOTE(lyarwood): Only available from v1.3.4 + if self._host.has_min_version( + MIN_LIBVIRT_MIGRATE_PARAM_PERSIST_XML + ): + params['persistent_xml'] = new_xml_str + # TODO(sahid): This should be in # post_live_migration_at_source but no way to retrieve # ports acquired on the host for the guest at this