Merge "Make QEMU_IMG_LIMITS process limits configurable"

nova/conf/libvirt.py

@@ -1098,6 +1098,12 @@ Requires:
 * Qemu >= 1.5 (raw format)
 * Qemu >= 1.6 (qcow2 format)
 """),
+    cfg.IntOpt('images_cpu_time_limit',
+               default=30,
+               help='CPU time process limit in seconds for qemu-img'),
+    cfg.IntOpt('images_address_space_limit',
+               default=2,
+               help='Address space process limit in gigabytes for qemu-img'),
 ]
 
 libvirt_lvm_opts = [

nova/privsep/qemu.py

@@ -25,15 +25,18 @@ from oslo_concurrency import processutils
 from oslo_log import log as logging
 from oslo_utils import units
 
+import nova.conf
 from nova import exception
 from nova.i18n import _
 import nova.privsep.utils
 
 LOG = logging.getLogger(__name__)
 
+CONF = nova.conf.CONF
+
 QEMU_IMG_LIMITS = processutils.ProcessLimits(
-    cpu_time=30,
-    address_space=1 * units.Gi)
+    cpu_time=CONF.libvirt.images_cpu_time_limit,
+    address_space=CONF.libvirt.images_address_space_limit * units.Gi)
 
 
 class EncryptionOptions(ty.TypedDict):

nova/tests/unit/privsep/test_qemu.py

@@ -13,9 +13,11 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import importlib
 from unittest import mock
 
 import ddt
+from oslo_utils import units
 
 import nova.privsep.qemu
 from nova import test
@@ -203,9 +205,24 @@ class QemuTestCase(test.NoDBTestCase):
         # Assert that the expected command is used
         mock_execute.assert_called_once_with(
             *expected_cmd, prlimit=nova.privsep.qemu.QEMU_IMG_LIMITS)
+        return mock_execute.call_args
 
     def test_privileged_qemu_img_info(self):
         self._test_qemu_img_info(nova.privsep.qemu.privileged_qemu_img_info)
 
     def test_unprivileged_qemu_img_info(self):
         self._test_qemu_img_info(nova.privsep.qemu.unprivileged_qemu_img_info)
+
+    def test_qemu_img_info_limits_config(self):
+        self.flags(images_cpu_time_limit=60, group='libvirt')
+        self.flags(images_address_space_limit=3, group='libvirt')
+        # Reload the nova.privsep.qemu module after setting the conf options
+        # because QEMU_IMG_LIMITS is global.
+        importlib.reload(nova.privsep.qemu)
+        # Save the call args of execute() to assert.
+        call_args = self._test_qemu_img_info(
+                nova.privsep.qemu.unprivileged_qemu_img_info)
+        # Verify that execute() was called with the configured values.
+        self.assertEqual(60, call_args.kwargs['prlimit'].cpu_time)
+        self.assertEqual(3 * units.Gi,
+                         call_args.kwargs['prlimit'].address_space)

releasenotes/notes/qemu-img-limits-config-dd49ea73c84a7cd4.yaml

@@ -0,0 +1,11 @@
+features:
+  - |
+    New configuration options ``[libvirt]images_cpu_time_limit`` and
+    ``[libvirt]images_address_space_limit`` have been added to enable tuning of
+    process limits for qemu-img. The default for
+    ``[libvirt]images_address_space_limit`` is increased from a hard-coded 1G
+    to 2G in order to accommodate larger image requirements in newer versions
+    of Ceph. For more details, see bug `#2116852`_.
+
+    .. _#2116852: https://bugs.launchpad.net/nova/+bug/2116852
+