Merge "Modify the mdevs in the migrate XML"
This commit is contained in:
Zuul
Gerrit Code Review
commit
060445aa2f
|
|
@ -293,6 +293,36 @@ Caveats
|
|||
This information is correct as of the 17.0.0 Queens release. Where
|
||||
improvements have been made or issues fixed, they are noted per item.
|
||||
|
||||
* When live-migrating an instance using vGPUs, the libvirt guest domain XML
|
||||
isn't updated with the new mediated device UUID to use for the target.
|
||||
|
||||
.. versionchanged:: 29.0.0
|
||||
|
||||
In the 2024.2 Caracal release, Nova now `supports vGPU live-migrations`_. In
|
||||
order to do this, both the source and target compute service need to have
|
||||
minimum versions of libvirt-8.6.0, QEMU-8.1.0 and Linux kernel 5.18.0. You
|
||||
need to ensure that either you use only single common vGPU type between two
|
||||
computes. Where multiple mdev types are configured on the source and
|
||||
destination host, custom traits or custom resource classes must be
|
||||
configured, reported by the host and requested by the instance to make sure
|
||||
that the Placement API correctly returns the supported GPU using the right
|
||||
vGPU type for a migration. Last but not least, if you want to live-migrate
|
||||
nVidia mediated devices, you need to update
|
||||
:oslo.config:option:`libvirt.live_migration_downtime`,
|
||||
:oslo.config:option:`libvirt.live_migration_downtime_steps` and
|
||||
:oslo.config:option:`libvirt.live_migration_downtime_delay`:
|
||||
|
||||
.. code-block:: ini
|
||||
|
||||
live_migration_downtime = 500000
|
||||
live_migration_downtime_steps = 3
|
||||
live_migration_downtime_delay = 3
|
||||
|
||||
You can see an example of a working live-migration `here`__.
|
||||
|
||||
.. __: http://sbauza.github.io/vgpu/vgpu_live_migration.html
|
||||
|
||||
|
||||
* Suspending a guest that has vGPUs doesn't yet work because of a libvirt
|
||||
limitation (it can't hot-unplug mediated devices from a guest). Workarounds
|
||||
using other instance actions (like snapshotting the instance or shelving it)
|
||||
|
|
@ -355,6 +385,7 @@ For nested vGPUs:
|
|||
.. _bug 1778563: https://bugs.launchpad.net/nova/+bug/1778563
|
||||
.. _bug 1762688: https://bugs.launchpad.net/nova/+bug/1762688
|
||||
.. _bug 1948705: https://bugs.launchpad.net/nova/+bug/1948705
|
||||
.. _supports vGPU live-migrations: https://specs.openstack.org/openstack/nova-specs/specs/2024.1/approved/libvirt-mdev-live-migrate.html
|
||||
|
||||
.. Links
|
||||
.. _Intel GVT-g: https://01.org/igvt-g
|
||||
|
|
|
|||
|
|
@ -576,10 +576,9 @@ class VGPULiveMigrationTests(base.LibvirtMigrationMixin, VGPUTestBase):
|
|||
mdevs = self.src.driver._get_all_assigned_mediated_devices(inst)
|
||||
self.assertEqual(1, len(mdevs))
|
||||
self._live_migrate(self.server, 'completed')
|
||||
# FIXME(sbauza): The domain is fully copied to the destination so the
|
||||
# XML contains the original mdev but given the 'devices' attribute on
|
||||
# the fixture doesn't have it, that's why we have a KeyError.
|
||||
self.assertRaises(KeyError, self.assert_mdev_usage, self.dest, 0)
|
||||
# Now the destination XML is updated, so the destination mdev is
|
||||
# correctly used.
|
||||
self.assert_mdev_usage(self.dest, 1)
|
||||
|
||||
|
||||
class VGPULiveMigrationTestsLMFailed(VGPULiveMigrationTests):
|
||||
|
|
|
|||
|
|
@ -190,6 +190,40 @@ class UtilityMigrationTestCase(test.NoDBTestCase):
|
|||
new_xml = new_xml.replace("/dev/dax0.2", "/dev/dax2.0")
|
||||
self.assertXmlEqual(res, new_xml)
|
||||
|
||||
def test_update_mdev_xml(self):
|
||||
xml_pattern = """<domain>
|
||||
<devices>
|
||||
<hostdev mode="subsystem" type="mdev" model="vfio-pci">
|
||||
<source>
|
||||
<address uuid="%s"/>
|
||||
</source>
|
||||
</hostdev>
|
||||
</devices>
|
||||
</domain>"""
|
||||
data = objects.LibvirtLiveMigrateData(
|
||||
target_mdevs={uuids.src_mdev: uuids.dst_mdev})
|
||||
doc = etree.fromstring(xml_pattern % uuids.src_mdev)
|
||||
res = migration._update_mdev_xml(doc, data.target_mdevs)
|
||||
self.assertEqual(xml_pattern % uuids.dst_mdev,
|
||||
etree.tostring(res, encoding='unicode'))
|
||||
|
||||
def test_update_mdev_xml_fails_on_notfound_mdev(self):
|
||||
xml_pattern = """<domain>
|
||||
<devices>
|
||||
<hostdev mode="subsystem" type="mdev" model="vfio-pci">
|
||||
<source>
|
||||
<address uuid="%s"/>
|
||||
</source>
|
||||
</hostdev>
|
||||
</devices>
|
||||
</domain>"""
|
||||
data = objects.LibvirtLiveMigrateData(
|
||||
target_mdevs={uuids.other_mdev: uuids.dst_mdev})
|
||||
doc = etree.fromstring(xml_pattern % uuids.src_mdev)
|
||||
# src_mdev UUID doesn't exist in target_mdevs dict
|
||||
self.assertRaises(exception.NovaException,
|
||||
migration._update_mdev_xml, doc, data.target_mdevs)
|
||||
|
||||
def test_update_numa_xml(self):
|
||||
doc = etree.fromstring("""
|
||||
<domain>
|
||||
|
|
|
|||
|
|
@ -67,6 +67,8 @@ def get_updated_guest_xml(instance, guest, migrate_data, get_volume_config,
|
|||
xml_doc = _update_vif_xml(xml_doc, migrate_data, get_vif_config)
|
||||
if 'dst_numa_info' in migrate_data:
|
||||
xml_doc = _update_numa_xml(xml_doc, migrate_data)
|
||||
if 'target_mdevs' in migrate_data:
|
||||
xml_doc = _update_mdev_xml(xml_doc, migrate_data.target_mdevs)
|
||||
if new_resources:
|
||||
xml_doc = _update_device_resources_xml(xml_doc, new_resources)
|
||||
return etree.tostring(xml_doc, encoding='unicode')
|
||||
|
|
@ -106,6 +108,28 @@ def _update_vpmems_xml(xml_doc, vpmems):
|
|||
return xml_doc
|
||||
|
||||
|
||||
def _update_mdev_xml(xml_doc, target_mdevs):
|
||||
for dev in xml_doc.findall('./devices/hostdev'):
|
||||
if dev.get('type') == 'mdev':
|
||||
address_tag = dev.find('source/address')
|
||||
if address_tag is None:
|
||||
continue
|
||||
src_mdev = address_tag.get('uuid')
|
||||
if src_mdev is not None:
|
||||
dst_mdev = target_mdevs.get(src_mdev)
|
||||
if dst_mdev is None:
|
||||
# For some reason, we don't know which mdev to use
|
||||
# so we prefer to abort the live-migration.
|
||||
raise exception.NovaException(
|
||||
'Unable to find the destination mediated device UUID '
|
||||
'to use for this source mdev UUID : %s' % src_mdev)
|
||||
else:
|
||||
address_tag.set('uuid', dst_mdev)
|
||||
LOG.debug('_update_mdev_xml output xml=%s',
|
||||
etree.tostring(xml_doc, encoding='unicode', pretty_print=True))
|
||||
return xml_doc
|
||||
|
||||
|
||||
def _update_numa_xml(xml_doc, migrate_data):
|
||||
LOG.debug('_update_numa_xml input xml=%s',
|
||||
etree.tostring(xml_doc, encoding='unicode', pretty_print=True))
|
||||
|
|
|
|||
|
|
@ -0,0 +1,13 @@
|
|||
---
|
||||
features:
|
||||
- |
|
||||
Instances using vGPUs can now be correctly live-migrated by the libvirt
|
||||
driver between compute nodes supporting the same mediated device types used
|
||||
by the instance. In order to be able to do this, the compute hosts need to
|
||||
support at least the minimum versions of libvirt-8.6.0, QEMU-8.1.0 and
|
||||
Linux kernel 5.18.0. If operators use multiple vGPU types per compute, they
|
||||
need to make sure they already use custom traits or custom resource classes
|
||||
for the GPUs resource providers and that the instance was created with a
|
||||
flavor using either a custom resource class or asking for a custom trait in
|
||||
order to make sure that Placement API will provide the right target GPU
|
||||
using the same mdev type for the instance.
|
||||
Loading…
Reference in New Issue