openstack/nova
Code Issues Proposed changes

Fix failure to boot instances with qcow2 format images

Browse Source 
Ceph doesn't support QCOW2 for hosting a virtual machine
disk:

  http://docs.ceph.com/docs/master/rbd/rbd-openstack/

When we set image_type as rbd and force_raw_images as
False and we don't launch an instance with boot-from-volume,
the instance is spawned using qcow2 as root disk but
fails to boot because data is accessed as raw.

To fix this, we raise an error and refuse to start
nova-compute service when force_raw_images and
image_type are incompatible.
When we import image into rbd, check the format of cache
images. If the format is not raw, remove it first and
fetch it again. It will be raw format now.

Change-Id: I1aa471e8df69fbb6f5d9aeb35651bd32c7123d78
Closes-Bug: 1816686
This commit is contained in:
zhu.boxiang 2019-03-01 16:16:31 +08:00
parent 3de296389a
commit 6c6ffc0476
8 changed files with 110 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
nova/conf/compute.py
View File

@ -232,6 +232,9 @@ Possible values:
Related options:
* ``compute_driver``: Only the libvirt driver uses this option.
* ``[libvirt]/images_type``: If images_type is rbd, setting this option
to False is not allowed. See the bug
https://bugs.launchpad.net/nova/+bug/1816686 for more details.
"""),
# NOTE(yamahata): ListOpt won't work because the command may include a comma.
# For example:

1
nova/conf/libvirt.py
View File

@ -856,6 +856,7 @@ Related options:
* compute.use_cow_images
* images_volume_group
* [workarounds]/ensure_libvirt_rbd_instance_dir_cleanup
* compute.force_raw_images
"""),
cfg.StrOpt('images_volume_group',
help="""

4
nova/exception.py
View File

@ -187,6 +187,10 @@ class Invalid(NovaException):
code = 400
class InvalidConfiguration(Invalid):
msg_fmt = _("Configuration is Invalid.")
class InvalidBDM(Invalid):
msg_fmt = _("Block Device Mapping is Invalid.")

46
nova/tests/unit/virt/libvirt/test_imagebackend.py
View File

@ -1411,12 +1411,44 @@ class RbdTestCase(_ImageTestCase, test.NoDBTestCase):
mock_exists.assert_has_calls([mock.call(), mock.call()])
fn.assert_called_once_with(target=self.TEMPLATE_PATH)
@mock.patch.object(images, 'qemu_img_info')
@mock.patch.object(os.path, 'exists', return_value=False)
def test__remove_non_raw_cache_image_not_exists(
self, mock_exists, mock_qemu):
image = self.image_class(self.INSTANCE, self.NAME)
image._remove_non_raw_cache_image(self.TEMPLATE_PATH)
mock_qemu.assert_not_called()
@mock.patch.object(os, 'remove')
@mock.patch.object(images, 'qemu_img_info',
return_value=imageutils.QemuImgInfo())
@mock.patch.object(os.path, 'exists', return_value=True)
def test__remove_non_raw_cache_image_with_raw_cache(
self, mock_exists, mock_qemu, mock_remove):
mock_qemu.return_value.file_format = 'raw'
image = self.image_class(self.INSTANCE, self.NAME)
image._remove_non_raw_cache_image(self.TEMPLATE_PATH)
mock_remove.assert_not_called()
@mock.patch.object(os, 'remove')
@mock.patch.object(images, 'qemu_img_info',
return_value=imageutils.QemuImgInfo())
@mock.patch.object(os.path, 'exists', return_value=True)
def test__remove_non_raw_cache_image_with_qcow2_cache(
self, mock_exists, mock_qemu, mock_remove):
mock_qemu.return_value.file_format = 'qcow2'
image = self.image_class(self.INSTANCE, self.NAME)
image._remove_non_raw_cache_image(self.TEMPLATE_PATH)
mock_remove.assert_called_once_with(self.TEMPLATE_PATH)
@mock.patch.object(images, 'qemu_img_info',
return_value=imageutils.QemuImgInfo())
@mock.patch.object(rbd_utils.RBDDriver, 'resize')
@mock.patch.object(imagebackend.Rbd, 'verify_base_size')
@mock.patch.object(imagebackend.Rbd, 'get_disk_size')
@mock.patch.object(imagebackend.Rbd, 'exists')
def test_create_image_resize(self, mock_exists, mock_get,
mock_verify, mock_resize):
mock_verify, mock_resize, mock_qemu):
fn = mock.MagicMock()
full_size = self.SIZE * 2
@ -1427,6 +1459,7 @@ class RbdTestCase(_ImageTestCase, test.NoDBTestCase):
image = self.image_class(self.INSTANCE, self.NAME)
mock_exists.return_value = False
mock_qemu.return_value.file_format = 'raw'
mock_get.return_value = self.SIZE
rbd_name = "%s_%s" % (self.INSTANCE['uuid'], self.NAME)
cmd = ('rbd', 'import', '--pool', self.POOL, self.TEMPLATE_PATH,
@ -1443,13 +1476,17 @@ class RbdTestCase(_ImageTestCase, test.NoDBTestCase):
mock_verify.assert_called_once_with(self.TEMPLATE_PATH, full_size)
fn.assert_called_once_with(target=self.TEMPLATE_PATH)
@mock.patch.object(images, 'qemu_img_info',
return_value=imageutils.QemuImgInfo())
@mock.patch.object(imagebackend.Rbd, 'get_disk_size')
@mock.patch.object(imagebackend.Rbd, 'exists')
def test_create_image_already_exists(self, mock_exists, mock_get):
def test_create_image_already_exists(self, mock_exists, mock_get,
mock_qemu):
rbd_utils.rbd.RBD_FEATURE_LAYERING = 1
image = self.image_class(self.INSTANCE, self.NAME)
mock_exists.return_value = True
mock_qemu.return_value.file_format = 'raw'
mock_get.return_value = self.SIZE
rbd_name = "%s_%s" % (self.INSTANCE['uuid'], self.NAME)
fn = mock.MagicMock()
@ -1507,7 +1544,10 @@ class RbdTestCase(_ImageTestCase, test.NoDBTestCase):
self.assertEqual(2361393152, image.get_disk_size(image.path))
size_mock.assert_called_once_with(image.rbd_name)
def test_create_image_too_small(self):
@mock.patch.object(images, 'qemu_img_info',
return_value=imageutils.QemuImgInfo())
def test_create_image_too_small(self, mock_qemu):
mock_qemu.return_value.file_format = 'raw'
image = self.image_class(self.INSTANCE, self.NAME)
with mock.patch.object(image, 'driver') as driver_mock:
driver_mock.exists.return_value = True

15
nova/tests/unit/virt/test_virt_drivers.py
View File

@ -901,6 +901,21 @@ class LibvirtConnTestCase(_VirtDriverTestCase, test.TestCase):
# stub out the unplug call to os-vif since we don't care about it.
self.stub_out('os_vif.unplug', lambda a, kw: None)
def test_init_host_image_type_rbd_force_raw_images_true(self):
CONF.set_override('images_type', 'rbd', group='libvirt')
CONF.set_override('force_raw_images', True)
self.connection.init_host('myhostname')
def test_init_host_image_type_non_rbd(self):
CONF.set_override('images_type', 'default', group='libvirt')
self.connection.init_host('myhostname')
def test_init_host_raise_invalid_configuration(self):
CONF.set_override('images_type', 'rbd', group='libvirt')
CONF.set_override('force_raw_images', False)
self.assertRaises(exception.InvalidConfiguration,
self.connection.init_host, 'myhostname')
def test_force_hard_reboot(self):
self.flags(wait_soft_reboot_seconds=0, group='libvirt')
self.test_reboot()

12
nova/virt/libvirt/driver.py
View File

@ -612,6 +612,18 @@ class LibvirtDriver(driver.ComputeDriver):
"'live_migration_with_native_tls'.")
raise exception.Invalid(msg)
# Some imagebackends are only able to import raw disk images,
# and will fail if given any other format. See the bug
# https://bugs.launchpad.net/nova/+bug/1816686 for more details.
if CONF.libvirt.images_type in ('rbd',):
if not CONF.force_raw_images:
msg = _("'[DEFAULT]/force_raw_images = False' is not "
"allowed with '[libvirt]/images_type = rbd'. "
"Please check the two configs and if you really "
"do want to use rbd as images_type, set "
"force_raw_images to True.")
raise exception.InvalidConfiguration(msg)
# TODO(sbauza): Remove this code once mediated devices are persisted
# across reboots.
if self._host.has_min_version(MIN_LIBVIRT_MDEV_SUPPORT):

19
nova/virt/libvirt/imagebackend.py
View File

@ -914,9 +914,28 @@ class Rbd(Image):
"""
return self.driver.size(self.rbd_name)
@staticmethod
def _remove_non_raw_cache_image(base):
# NOTE(boxiang): If the cache image file exists, we will check
# the format of it. Only raw format image is compatible for
# RBD image backend. If format is not raw, we will remove it
# at first. We limit force_raw_images to True this time. So
# the format of new cache image must be raw.
# We can remove this in 'U' version later.
if not os.path.exists(base):
return True
image_format = images.qemu_img_info(base)
if image_format.file_format != 'raw':
try:
os.remove(base)
except OSError as e:
LOG.warning("Ignoring failure to remove %(path)s: "
"%(error)s", {'path': base, 'error': e})
def create_image(self, prepare_template, base, size, *args, **kwargs):
if not self.exists():
self._remove_non_raw_cache_image(base)
prepare_template(target=base, *args, **kwargs)
# prepare_template() may have cloned the image into a new rbd

13
releasenotes/notes/bug-1816686-77060eb8f8bd4092.yaml Normal file
View File

@ -0,0 +1,13 @@
---
upgrade:
- |
The libvirt driver's RBD imagebackend no longer supports setting
force_raw_images to False. Setting force_raw_images = False and
images_type = rbd in nova.conf will cause the nova compute service
to refuse to start. To fix this, set force_raw_images = True. This
change was required to fix the `bug 1816686`_.
Note that non-raw cache image files will be removed if you set
force_raw_images = True and images_type = rbd now.
.. _bug 1816686: https://bugs.launchpad.net/nova/+bug/1816686