openstack
/
nova
Code Issues Proposed changes

libvirt: Use os.stat and os.path.getsize for RAW disk inspection 

At present when inspecting a file based image we always use ``qemu-img`` to
determine the virtual size of the image. This works well but can lead to
the resource tracker taking considerable time to update on hosts with
a large number of instances/images.

This change switches to using os.stat and os.path.getsize to determine
the allocated and virtual disk sizes of RAW disks.

Future changes will look into caching the virtual size of the disk
within disk.info locally on the host to also improve this for qcow2 and
ploop, further simplifying this code path.

Closes-bug: #1785827
Change-Id: Ic5c41493dcdcd807209be2beaae0dbbdf5d2ba3f
(cherry picked from commit e6af812865)
(cherry picked from commit bda6173a84)
This commit is contained in:
Lee Yarwood 2018-08-09 13:45:13 +01:00 committed by Vlad Gusev
parent d085c8fe53
commit b58805753a
2 changed files with 73 additions and 54 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

79
nova/tests/unit/virt/libvirt/test_driver.py
View File

@ -4350,12 +4350,12 @@ class LibvirtConnTestCase(test.NoDBTestCase,
[mock.call(host='127.0.0.1', port=10000),
mock.call(host='127.0.0.1', port=10001)])
@mock.patch('nova.virt.disk.api.get_disk_info',
return_value=mock.Mock(disk_size=0))
@mock.patch('os.stat', return_value=mock.Mock(st_blocks=0))
@mock.patch('os.path.getsize', return_value=0)
@mock.patch('nova.virt.libvirt.storage.lvm.get_volume_size',
return_value='fake-size')
def test_detach_encrypted_volumes(self, mock_get_volume_size,
mock_getsize):
mock_getsize, mock_stat):
"""Test that unencrypted volumes are not disconnected with dmcrypt."""
instance = objects.Instance(**self.test_instance)
xml = """
@ -8845,9 +8845,15 @@ class LibvirtConnTestCase(test.NoDBTestCase,
return mock_virDomain
mock_lookup.side_effect = mock_lookup_side_effect
mock_qemu_img_info = mock.Mock(disk_size=10737418240,
virtual_size=10737418240)
return (mock_qemu_img_info, mock_lookup)
mock_qemu_img_info = mock.Mock()
mock_qemu_img_info.return_value = mock.Mock(disk_size=10737418240,
virtual_size=10737418240)
mock_stat = mock.Mock()
mock_stat.return_value = mock.Mock(st_blocks=20971520)
mock_get_size = mock.Mock()
mock_get_size.return_value = 10737418240
return (mock_stat, mock_get_size, mock_qemu_img_info, mock_lookup)
def test_is_shared_block_storage_rbd(self):
self.flags(images_type='rbd', group='libvirt')
@ -8940,7 +8946,7 @@ class LibvirtConnTestCase(test.NoDBTestCase,
{'connection_info': 'info', 'mount_device': '/dev/vda'}]}
instance = objects.Instance(**self.test_instance)
drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
(mock_qemu_img_info, mock_lookup) =\
(mock_stat, mock_get_size, mock_qemu_img_info, mock_lookup) =\
self._is_shared_block_storage_test_create_mocks(disks)
data = objects.LibvirtLiveMigrateData(is_volume_backed=True,
is_shared_instance_path=False)
@ -8964,18 +8970,21 @@ class LibvirtConnTestCase(test.NoDBTestCase,
{'connection_info': 'info', 'mount_device': '/dev/vda'}]}
instance = objects.Instance(**self.test_instance)
drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
(mock_qemu_img_info, mock_lookup) =\
(mock_stat, mock_get_size, mock_qemu_img_info, mock_lookup) =\
self._is_shared_block_storage_test_create_mocks(disks)
data = objects.LibvirtLiveMigrateData(is_volume_backed=True,
is_shared_instance_path=False)
with test.nested(
mock.patch('os.stat', mock_stat),
mock.patch('os.path.getsize', mock_get_size),
mock.patch.object(libvirt_driver.disk_api,
'get_disk_info', mock_qemu_img_info),
mock.patch.object(host.Host, '_get_domain', mock_lookup)):
self.assertFalse(drvr._is_shared_block_storage(
instance, data,
block_device_info = bdi))
mock_qemu_img_info.assert_called_once_with('/instance/disk.local')
mock_stat.assert_called_once_with('/instance/disk.local')
mock_get_size.assert_called_once_with('/instance/disk.local')
mock_lookup.assert_called_once_with(instance)
def test_is_shared_block_storage_nfs(self):
@ -11485,8 +11494,11 @@ class LibvirtConnTestCase(test.NoDBTestCase,
migrate_data=migrate_data)
self.assertEqual(['cmt'], res.supported_perf_events)
@mock.patch('os.stat')
@mock.patch('os.path.getsize')
@mock.patch('nova.virt.disk.api.get_disk_info')
def test_get_instance_disk_info_works_correctly(self, mock_qemu_img_info):
def test_get_instance_disk_info_works_correctly(self, mock_qemu_img_info,
mock_get_size, mock_stat):
# Test data
instance = objects.Instance(**self.test_instance)
dummyxml = ("<domain type='kvm'><name>instance-0000000a</name>"
@ -11503,10 +11515,10 @@ class LibvirtConnTestCase(test.NoDBTestCase,
vdmock = mock.Mock(autospec=fakelibvirt.virDomain)
vdmock.XMLDesc.return_value = dummyxml
mock_qemu_img_info.side_effect = [
mock.Mock(disk_size=10737418240, virtual_size=10737418240),
mock.Mock(disk_size=3328599655, virtual_size=21474836480)
]
mock_qemu_img_info.return_value = mock.Mock(disk_size=3328599655,
virtual_size=21474836480)
mock_stat.return_value = mock.Mock(st_blocks=20971520)
mock_get_size.return_value = 10737418240
def fake_lookup(_uuid):
if _uuid == instance.uuid:
@ -11523,18 +11535,20 @@ class LibvirtConnTestCase(test.NoDBTestCase,
self.assertEqual(info[0]['type'], 'raw')
self.assertEqual(info[0]['path'], '/test/disk')
self.assertEqual(info[0]['disk_size'], 10737418240)
self.assertEqual(info[0]['virt_disk_size'], 10737418240)
self.assertEqual(info[0]['backing_file'], "")
self.assertEqual(info[0]['over_committed_disk_size'], 0)
self.assertEqual(info[1]['type'], 'qcow2')
self.assertEqual(info[1]['path'], '/test/disk.local')
self.assertEqual(info[1]['disk_size'], 3328599655)
self.assertEqual(info[1]['virt_disk_size'], 21474836480)
self.assertEqual(info[1]['backing_file'], "file")
self.assertEqual(info[1]['over_committed_disk_size'], 18146236825)
vdmock.XMLDesc.assert_called_once_with(0)
mock_qemu_img_info.assert_has_calls([mock.call('/test/disk'),
mock.call('/test/disk.local')])
self.assertEqual(2, mock_qemu_img_info.call_count)
mock_qemu_img_info.called_once_with('/test/disk.local')
mock_stat.called_once_with('/test/disk')
mock_get_size.called_once_with('/test/disk')
def test_post_live_migration(self):
vol = {'block_device_mapping': [
@ -11621,9 +11635,11 @@ class LibvirtConnTestCase(test.NoDBTestCase,
instance)
_test()
@mock.patch('os.stat')
@mock.patch('os.path.getsize')
@mock.patch('nova.virt.disk.api.get_disk_info')
def test_get_instance_disk_info_excludes_volumes(
self, mock_qemu_img_info):
self, mock_qemu_img_info, mock_get_size, mock_stat):
# Test data
instance = objects.Instance(**self.test_instance)
dummyxml = ("<domain type='kvm'><name>instance-0000000a</name>"
@ -11646,10 +11662,10 @@ class LibvirtConnTestCase(test.NoDBTestCase,
vdmock = mock.Mock(autospec=fakelibvirt.virDomain)
vdmock.XMLDesc.return_value = dummyxml
mock_qemu_img_info.side_effect = [
mock.Mock(disk_size=10737418240, virtual_size=10737418240),
mock.Mock(disk_size=3328599655, virtual_size=21474836480)
]
mock_qemu_img_info.return_value = mock.Mock(disk_size=3328599655,
virtual_size=21474836480)
mock_stat.return_value = mock.Mock(st_blocks=20971520)
mock_get_size.return_value = 10737418240
def fake_lookup(_uuid):
if _uuid == instance.uuid:
@ -11680,12 +11696,14 @@ class LibvirtConnTestCase(test.NoDBTestCase,
self.assertEqual(info[1]['over_committed_disk_size'], 18146236825)
vdmock.XMLDesc.assert_called_once_with(0)
mock_qemu_img_info.assert_has_calls([mock.call('/test/disk'),
mock.call('/test/disk.local')])
self.assertEqual(2, mock_qemu_img_info.call_count)
mock_qemu_img_info.assert_called_once_with('/test/disk.local')
mock_stat.assert_called_once_with('/test/disk')
mock_get_size.assert_called_once_with('/test/disk')
@mock.patch('nova.virt.disk.api.get_disk_info')
def test_get_instance_disk_info_no_bdinfo_passed(self, mock_qemu_img_info):
@mock.patch('os.stat')
@mock.patch('os.path.getsize')
def test_get_instance_disk_info_no_bdinfo_passed(self, mock_get_size,
mock_stat):
# NOTE(ndipanov): _get_disk_overcomitted_size_total calls this method
# without access to Nova's block device information. We want to make
# sure that we guess volumes mostly correctly in that case as well
@ -11706,8 +11724,8 @@ class LibvirtConnTestCase(test.NoDBTestCase,
vdmock = mock.Mock(autospec=fakelibvirt.virDomain)
vdmock.XMLDesc.return_value = dummyxml
mock_qemu_img_info.return_value = mock.Mock(disk_size=10737418240,
virtual_size=10737418240)
mock_stat.return_value = mock.Mock(st_blocks=20971520)
mock_get_size.return_value = 10737418240
def fake_lookup(_uuid):
if _uuid == instance.uuid:
@ -11727,7 +11745,8 @@ class LibvirtConnTestCase(test.NoDBTestCase,
self.assertEqual(info[0]['over_committed_disk_size'], 0)
vdmock.XMLDesc.assert_called_once_with(0)
mock_qemu_img_info.assert_called_once_with(path)
mock_stat.assert_called_once_with(path)
mock_get_size.assert_called_once_with(path)
def test_spawn_with_network_info(self):
def fake_getLibVersion():

48
nova/virt/libvirt/driver.py
View File

@ -7856,42 +7856,42 @@ class LibvirtDriver(driver.ComputeDriver):
driver_type = device.driver_format
# get the real disk size or
# raise a localized error if image is unavailable
if disk_type == 'file':
if disk_type == 'file' and driver_type == 'ploop':
dk_size = 0
for dirpath, dirnames, filenames in os.walk(path):
for f in filenames:
fp = os.path.join(dirpath, f)
dk_size += os.path.getsize(fp)
qemu_img_info = disk_api.get_disk_info(path)
if driver_type == 'ploop':
dk_size = 0
for dirpath, dirnames, filenames in os.walk(path):
for f in filenames:
fp = os.path.join(dirpath, f)
dk_size += os.path.getsize(fp)
else:
dk_size = qemu_img_info.disk_size
# NOTE(lyarwood): Fetch the virtual size for all file disks.
virt_size = qemu_img_info.virtual_size
backing_file = libvirt_utils.get_disk_backing_file(path)
over_commit_size = int(virt_size) - dk_size
elif disk_type == 'file' and driver_type == 'qcow2':
qemu_img_info = disk_api.get_disk_info(path)
dk_size = qemu_img_info.disk_size
virt_size = qemu_img_info.virtual_size
backing_file = libvirt_utils.get_disk_backing_file(path)
over_commit_size = int(virt_size) - dk_size
elif disk_type == 'file':
dk_size = os.stat(path).st_blocks * 512
virt_size = os.path.getsize(path)
backing_file = ""
over_commit_size = 0
elif disk_type == 'block' and block_device_info:
# FIXME(lyarwood): There's no reason to use a separate call
# here, once disk_api uses privsep this should be removed along
# with the surrounding conditionals to simplify this mess.
dk_size = lvm.get_volume_size(path)
# NOTE(lyarwood): As above, we should be using disk_api to
# fetch the virt-size but can't as it currently runs qemu-img
# as an unprivileged user, causing a failure for block devices.
virt_size = dk_size
backing_file = ""
over_commit_size = 0
else:
LOG.debug('skipping disk %(path)s (%(target)s) - unable to '
'determine if volume',
{'path': path, 'target': target})
continue
if driver_type in ("qcow2", "ploop"):
backing_file = libvirt_utils.get_disk_backing_file(path)
over_commit_size = int(virt_size) - dk_size
else:
backing_file = ""
over_commit_size = 0
disk_info.append({'type': driver_type,
'path': path,
'virt_disk_size': virt_size,