From bbf9d1de06e9991acd968fceee899a8df3776d60 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. NOTE(lyarwood): A simple change to test_migrate_v3_unicode is included as Iccce0ab50eee515e533ab36c8e7adc10cb3f7019 had removed this from master. Co-authored-by: Tadayoshi Hosoya Closes-Bug: #1890501 Change-Id: Ia3f1d8e83cbc574ce5cb440032e12bbcb1e10e98 (cherry picked from commit 1bb8ee95d4c3ddc3f607ac57526b75af1b7fbcff) --- nova/tests/unit/virt/libvirt/test_driver.py | 8 +++++++- nova/tests/unit/virt/libvirt/test_guest.py | 2 ++ nova/virt/libvirt/guest.py | 1 + 3 files changed, 10 insertions(+), 1 deletion(-) diff --git a/nova/tests/unit/virt/libvirt/test_driver.py b/nova/tests/unit/virt/libvirt/test_driver.py index b416641d3629..99ce85a870b0 100644 --- a/nova/tests/unit/virt/libvirt/test_driver.py +++ b/nova/tests/unit/virt/libvirt/test_driver.py @@ -11196,6 +11196,7 @@ class LibvirtConnTestCase(test.NoDBTestCase, 'migrate_disks': disk_paths, 'bandwidth': _bandwidth, 'destination_xml': target_xml, + 'persistent_xml': target_xml, } # start test @@ -11303,7 +11304,8 @@ class LibvirtConnTestCase(test.NoDBTestCase, 'migrate_disks': disk_paths, 'migrate_uri': 'tcp://127.0.0.2', 'bandwidth': CONF.libvirt.live_migration_bandwidth, - 'destination_xml': target_xml + 'destination_xml': target_xml, + 'persistent_xml': target_xml, } # Start test @@ -11462,6 +11464,7 @@ class LibvirtConnTestCase(test.NoDBTestCase, 'migrate_uri': 'tcp://127.0.0.2', 'bandwidth': CONF.libvirt.live_migration_bandwidth, 'destination_xml': target_xml, + 'persistent_xml': target_xml, } # start test @@ -11813,6 +11816,7 @@ class LibvirtConnTestCase(test.NoDBTestCase, 'migrate_disks': ['vda', 'vdb'], 'bandwidth': CONF.libvirt.live_migration_bandwidth, 'destination_xml': target_xml, + 'persistent_xml': target_xml, } # start test @@ -11939,6 +11943,7 @@ class LibvirtConnTestCase(test.NoDBTestCase, 'migrate_disks': device_names, 'bandwidth': CONF.libvirt.live_migration_bandwidth, 'destination_xml': '', + 'persistent_xml': '', } if not params['migrate_disks']: del params['migrate_disks'] @@ -12078,6 +12083,7 @@ class LibvirtConnTestCase(test.NoDBTestCase, 'migrate_disks': disk_paths, 'bandwidth': CONF.libvirt.live_migration_bandwidth, 'destination_xml': '', + 'persistent_xml': '', } # Prepare mocks diff --git a/nova/tests/unit/virt/libvirt/test_guest.py b/nova/tests/unit/virt/libvirt/test_guest.py index 55642c66f664..51899b730b3e 100644 --- a/nova/tests/unit/virt/libvirt/test_guest.py +++ b/nova/tests/unit/virt/libvirt/test_guest.py @@ -682,6 +682,7 @@ class GuestTestCase(test.NoDBTestCase): 'an-uri', flags=1, params={'migrate_uri': 'dest-uri', 'migrate_disks': 'disk1', 'destination_xml': '', + 'persistent_xml': '', 'bandwidth': 2}) @testtools.skipIf(not six.PY2, 'libvirt python3 bindings accept unicode') @@ -699,6 +700,7 @@ class GuestTestCase(test.NoDBTestCase): 'migrate_disks': ['disk1', 'disk2'], 'destination_xml': expect_dest_xml, + 'persistent_xml': expect_dest_xml, 'bandwidth': 2}) def test_abort_job(self): diff --git a/nova/virt/libvirt/guest.py b/nova/virt/libvirt/guest.py index 0d485eb86d98..465932473031 100644 --- a/nova/virt/libvirt/guest.py +++ b/nova/virt/libvirt/guest.py @@ -638,6 +638,7 @@ class Guest(object): if destination_xml: params['destination_xml'] = destination_xml + params['persistent_xml'] = destination_xml if migrate_disks: params['migrate_disks'] = migrate_disks if migrate_uri: