From b9ea91d17703f5b324a50727b6503ace0f4e95eb 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. 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) --- 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 29b826e93452..85a237bd7229 100644 --- a/nova/tests/unit/virt/libvirt/test_driver.py +++ b/nova/tests/unit/virt/libvirt/test_driver.py @@ -9902,6 +9902,7 @@ class LibvirtConnTestCase(test.NoDBTestCase, 'migrate_disks': disk_paths, 'bandwidth': _bandwidth, 'destination_xml': target_xml, + 'persistent_xml': target_xml, } # start test @@ -10009,7 +10010,8 @@ 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 @@ -10109,6 +10111,7 @@ 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 @@ -10459,6 +10462,7 @@ class LibvirtConnTestCase(test.NoDBTestCase, 'migrate_disks': ['vda', 'vdb'], 'bandwidth': CONF.libvirt.live_migration_bandwidth, 'destination_xml': target_xml, + 'persistent_xml': target_xml, } # start test @@ -10585,6 +10589,7 @@ 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'] @@ -10724,6 +10729,7 @@ 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 8d45ec66abb6..62f5b3bb0c6d 100644 --- a/nova/tests/unit/virt/libvirt/test_guest.py +++ b/nova/tests/unit/virt/libvirt/test_guest.py @@ -699,6 +699,7 @@ 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') @@ -716,6 +717,7 @@ 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 8da7015e4e3f..34b867738b5f 100644 --- a/nova/virt/libvirt/guest.py +++ b/nova/virt/libvirt/guest.py @@ -654,6 +654,7 @@ 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: