diff --git a/doc/source/admin/resource-limits.rst b/doc/source/admin/resource-limits.rst index c74ad31c17bc..8ef248a9a1d2 100644 --- a/doc/source/admin/resource-limits.rst +++ b/doc/source/admin/resource-limits.rst @@ -38,7 +38,8 @@ CPU limits Libvirt enforces CPU limits in terms of *shares* and *quotas*, configured via :nova:extra-spec:`quota:cpu_shares` and :nova:extra-spec:`quota:cpu_period` / :nova:extra-spec:`quota:cpu_quota`, respectively. Both are implemented using -the `cgroups v1 cpu controller`__. +the `cgroups cpu controller`__. Note that allowed values for *shares* are +platform dependant. CPU shares are a proportional weighted share of total CPU resources relative to other instances. It does not limit CPU usage if CPUs are not busy. There is no diff --git a/nova/tests/unit/virt/libvirt/test_driver.py b/nova/tests/unit/virt/libvirt/test_driver.py index df9bc71fc40a..6dedf7ef4627 100644 --- a/nova/tests/unit/virt/libvirt/test_driver.py +++ b/nova/tests/unit/virt/libvirt/test_driver.py @@ -2991,7 +2991,7 @@ class LibvirtConnTestCase(test.NoDBTestCase, cfg = drvr._get_guest_config(instance_ref, [], image_meta, disk_info) self.assertIsNone(cfg.cpuset) - self.assertEqual(0, len(cfg.cputune.vcpupin)) + self.assertIsNone(cfg.cputune) self.assertIsNone(cfg.cpu.numa) @mock.patch('nova.privsep.utils.supports_direct_io', @@ -3028,7 +3028,7 @@ class LibvirtConnTestCase(test.NoDBTestCase, image_meta, disk_info) self.assertFalse(choice_mock.called) self.assertIsNone(cfg.cpuset) - self.assertEqual(0, len(cfg.cputune.vcpupin)) + self.assertIsNone(cfg.cputune) self.assertIsNone(cfg.cpu.numa) def _test_get_guest_memory_backing_config( @@ -3436,7 +3436,7 @@ class LibvirtConnTestCase(test.NoDBTestCase, cfg = conn._get_guest_config(instance_ref, [], image_meta, disk_info) self.assertEqual(set([3]), cfg.cpuset) - self.assertEqual(0, len(cfg.cputune.vcpupin)) + self.assertIsNone(cfg.cputune) self.assertIsNone(cfg.cpu.numa) @mock.patch('nova.privsep.utils.supports_direct_io', @@ -3490,7 +3490,7 @@ class LibvirtConnTestCase(test.NoDBTestCase, image_meta, disk_info) self.assertFalse(choice_mock.called) self.assertEqual(set([3]), cfg.cpuset) - self.assertEqual(0, len(cfg.cputune.vcpupin)) + self.assertIsNone(cfg.cputune) self.assertIsNone(cfg.cpu.numa) @mock.patch.object(fakelibvirt.Connection, 'getType') @@ -3589,7 +3589,7 @@ class LibvirtConnTestCase(test.NoDBTestCase, # NOTE(ndipanov): we make sure that pin_set was taken into account # when choosing viable cells self.assertEqual(set([2, 3]), cfg.cpuset) - self.assertEqual(0, len(cfg.cputune.vcpupin)) + self.assertIsNone(cfg.cputune) self.assertIsNone(cfg.cpu.numa) @mock.patch.object( @@ -3631,7 +3631,7 @@ class LibvirtConnTestCase(test.NoDBTestCase, cfg = drvr._get_guest_config(instance_ref, [], image_meta, disk_info) self.assertIsNone(cfg.cpuset) - self.assertEqual(0, len(cfg.cputune.vcpupin)) + self.assertIsNone(cfg.cputune) self.assertIsNone(cfg.numatune) self.assertIsNotNone(cfg.cpu.numa) for instance_cell, numa_cfg_cell in zip( @@ -7038,26 +7038,6 @@ class LibvirtConnTestCase(test.NoDBTestCase, [], image_meta, disk_info) - @mock.patch.object( - host.Host, "is_cpu_control_policy_capable", return_value=True) - def test_guest_cpu_shares_with_multi_vcpu(self, is_able): - self.flags(virt_type='kvm', group='libvirt') - - drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True) - - instance_ref = objects.Instance(**self.test_instance) - instance_ref.flavor.vcpus = 4 - image_meta = objects.ImageMeta.from_dict(self.test_image_meta) - - disk_info = blockinfo.get_disk_info(CONF.libvirt.virt_type, - instance_ref, - image_meta) - - cfg = drvr._get_guest_config(instance_ref, [], - image_meta, disk_info) - - self.assertEqual(4096, cfg.cputune.shares) - @mock.patch.object( host.Host, "is_cpu_control_policy_capable", return_value=True) def test_get_guest_config_with_cpu_quota(self, is_able): @@ -11689,7 +11669,7 @@ class LibvirtConnTestCase(test.NoDBTestCase, mock_migrateToURI3, mock_min_version): self.compute = manager.ComputeManager() - instance_ref = self.test_instance + instance_ref = objects.Instance(**self.test_instance) target_connection = '127.0.0.2' xml_tmpl = ("" @@ -12369,7 +12349,7 @@ class LibvirtConnTestCase(test.NoDBTestCase, mock_get, mock_min_version): self.compute = manager.ComputeManager() - instance_ref = self.test_instance + instance_ref = objects.Instance(**self.test_instance) target_connection = '127.0.0.2' xml_tmpl = ("" @@ -12659,7 +12639,7 @@ class LibvirtConnTestCase(test.NoDBTestCase, mock_min_version): # Prepare data self.compute = manager.ComputeManager() - instance_ref = self.test_instance + instance_ref = objects.Instance(**self.test_instance) target_connection = '127.0.0.2' disk_paths = ['vda', 'vdb'] diff --git a/nova/tests/unit/virt/libvirt/test_migration.py b/nova/tests/unit/virt/libvirt/test_migration.py index f4e64fbe53ed..70488f88cf43 100644 --- a/nova/tests/unit/virt/libvirt/test_migration.py +++ b/nova/tests/unit/virt/libvirt/test_migration.py @@ -28,6 +28,7 @@ from nova import objects from nova import test from nova.tests import fixtures as nova_fixtures from nova.tests.fixtures import libvirt as fakelibvirt +from nova.tests.unit.virt.libvirt import test_driver from nova.virt.libvirt import config as vconfig from nova.virt.libvirt import guest as libvirt_guest from nova.virt.libvirt import host @@ -80,16 +81,51 @@ class UtilityMigrationTestCase(test.NoDBTestCase): get_volume_config = mock.MagicMock() mock_guest.get_xml_desc.return_value = '' - migration.get_updated_guest_xml( - mock.sentinel.instance, mock_guest, data, get_volume_config) + instance = objects.Instance(**test_driver._create_test_instance()) + migration.get_updated_guest_xml(instance, mock_guest, data, + get_volume_config) mock_graphics.assert_called_once_with(mock.ANY, data) mock_serial.assert_called_once_with(mock.ANY, data) mock_volume.assert_called_once_with( - mock.ANY, data, mock.sentinel.instance, get_volume_config) + mock.ANY, data, instance, get_volume_config) mock_perf_events_xml.assert_called_once_with(mock.ANY, data) mock_memory_backing.assert_called_once_with(mock.ANY, data) self.assertEqual(1, mock_tostring.called) + def test_update_quota_xml(self): + old_xml = """ + fake-instance + + 42 + 1337 + + """ + instance = objects.Instance(**test_driver._create_test_instance()) + new_xml = migration._update_quota_xml(instance, + etree.fromstring(old_xml)) + new_xml = etree.tostring(new_xml, encoding='unicode') + self.assertXmlEqual( + """ + fake-instance + + 1337 + + """, new_xml) + + def test_update_quota_xml_empty_cputune(self): + old_xml = """ + fake-instance + + 42 + + """ + instance = objects.Instance(**test_driver._create_test_instance()) + new_xml = migration._update_quota_xml(instance, + etree.fromstring(old_xml)) + new_xml = etree.tostring(new_xml, encoding='unicode') + self.assertXmlEqual('fake-instance', + new_xml) + def test_update_device_resources_xml_vpmem(self): # original xml for vpmems, /dev/dax0.1 and /dev/dax0.2 here # are vpmem device path on source host diff --git a/nova/virt/libvirt/driver.py b/nova/virt/libvirt/driver.py index b35f17fe3ae4..132a24b7b7f0 100644 --- a/nova/virt/libvirt/driver.py +++ b/nova/virt/libvirt/driver.py @@ -5692,15 +5692,11 @@ class LibvirtDriver(driver.ComputeDriver): if not is_able or CONF.libvirt.virt_type not in ('lxc', 'kvm', 'qemu'): return - if guest.cputune is None: - guest.cputune = vconfig.LibvirtConfigGuestCPUTune() - # Setting the default cpu.shares value to be a value - # dependent on the number of vcpus - guest.cputune.shares = 1024 * guest.vcpus - for name in cputuning: key = "quota:cpu_" + name if key in flavor.extra_specs: + if guest.cputune is None: + guest.cputune = vconfig.LibvirtConfigGuestCPUTune() setattr(guest.cputune, name, int(flavor.extra_specs[key])) diff --git a/nova/virt/libvirt/migration.py b/nova/virt/libvirt/migration.py index 8cea9f298313..4726111a7658 100644 --- a/nova/virt/libvirt/migration.py +++ b/nova/virt/libvirt/migration.py @@ -62,6 +62,7 @@ def get_updated_guest_xml(instance, guest, migrate_data, get_volume_config, xml_doc, migrate_data, instance, get_volume_config) xml_doc = _update_perf_events_xml(xml_doc, migrate_data) xml_doc = _update_memory_backing_xml(xml_doc, migrate_data) + xml_doc = _update_quota_xml(instance, xml_doc) if get_vif_config is not None: xml_doc = _update_vif_xml(xml_doc, migrate_data, get_vif_config) if 'dst_numa_info' in migrate_data: @@ -71,6 +72,18 @@ def get_updated_guest_xml(instance, guest, migrate_data, get_volume_config, return etree.tostring(xml_doc, encoding='unicode') +def _update_quota_xml(instance, xml_doc): + flavor_shares = instance.flavor.extra_specs.get('quota:cpu_shares') + cputune = xml_doc.find('./cputune') + shares = xml_doc.find('./cputune/shares') + if shares is not None and not flavor_shares: + cputune.remove(shares) + # Remove the cputune element entirely if it has no children left. + if cputune is not None and not list(cputune): + xml_doc.remove(cputune) + return xml_doc + + def _update_device_resources_xml(xml_doc, new_resources): vpmems = [] for resource in new_resources: diff --git a/releasenotes/notes/remove-default-cputune-shares-values-85d5ddf4b8e24eaa.yaml b/releasenotes/notes/remove-default-cputune-shares-values-85d5ddf4b8e24eaa.yaml new file mode 100644 index 000000000000..9dd0987bb8c1 --- /dev/null +++ b/releasenotes/notes/remove-default-cputune-shares-values-85d5ddf4b8e24eaa.yaml @@ -0,0 +1,15 @@ +upgrade: + - | + In the libvirt driver, the default value of the ```` + element has been removed, and is now left to libvirt to decide. This is + because allowed values are platform dependant, and the previous code was + not guaranteed to be supported on all platforms. If any of your flavors are + using the quota:cpu_shares extra spec, you may need to resize to a + supported value before upgrading. + + To facilitate the transition to no Nova default for ````, + its value will be removed during live migration unless a value is set in + the ``quota:cpu_shares`` extra spec. This can cause temporary CPU + starvation for the live migrated instance if other instances on the + destination host still have the old default ```` value. To + fix this, hard reboot, cold migrate, or live migrate the other instances.