openstack/nova
Code Issues Proposed changes

Allow services to start with threading

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At the service startup nova need to initialize either the eventlet or
the threading backend of oslo.service. So this patch reuses the existing
logic behind OS_NOVA_DISABLE_EVENTLET_PATCHING.

When OS_NOVA_DISABLE_EVENTLET_PATCHING env variable is set to true the
service will select the threading backend otherwise the eventlet
backend.

Also to avoid later monkey patch calls to invalidated the selection if
the threading backend is selected then the monkey_patch code is
poisoned.

This patch also makes sure that oslo.messaging also initialized with the
matching executor backend.

As this is the last step to make nova-scheduler run in threading mode
this patch adds a release notes as well.

Change-Id: I6e2e6a43df78d23580b5e7402352a5036100ab36
Signed-off-by: Balazs Gibizer <gibi@redhat.com>
This commit is contained in:
Balazs Gibizer
2025-04-29 15:43:47 +02:00
committed by Dan Smith
parent eb823b8068
commit 5cbe39aca9
7 changed files with 116 additions and 18 deletions
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8
doc/source/conf.py
View File

@@ -188,11 +188,3 @@ openstackdocs_projects = [
'watcher',
]
# -- Custom extensions --------------------------------------------------------
# NOTE(mdbooth): (2019-03-20) Sphinx loads policies defined in setup.cfg, which
# includes the placement policy at nova/api/openstack/placement/policies.py.
# Loading this imports nova/api/openstack/__init__.py, which imports
# nova.monkey_patch, which will do eventlet monkey patching to the sphinx
# process. As well as being unnecessary and a bad idea, this breaks on
# python3.6 (but not python3.7), so don't do that.
os.environ['OS_NOVA_DISABLE_EVENTLET_PATCHING'] = '1'

48
nova/monkey_patch.py
View File

@@ -29,7 +29,8 @@ def is_patched():
def _monkey_patch():
if is_patched():
return
return False
# NOTE(mdbooth): Anything imported here will not be monkey patched. It is
# important to take care not to import anything here which requires monkey
# patching.
@@ -68,14 +69,45 @@ def _monkey_patch():
"importing and not executing nova code.",
', '.join(problems))
return True
def patch():
# NOTE(mdbooth): This workaround is required to avoid breaking sphinx. See
# separate comment in doc/source/conf.py. It may also be useful for other
# non-nova utilities. Ideally the requirement for this workaround will be
# removed as soon as possible, so do not rely on, or extend it.
if (os.environ.get('OS_NOVA_DISABLE_EVENTLET_PATCHING', '').lower()
not in ('1', 'true', 'yes')):
_monkey_patch()
global MONKEY_PATCHED
MONKEY_PATCHED = True
if _monkey_patch():
global MONKEY_PATCHED
MONKEY_PATCHED = True
import oslo_service.backend as service
service.init_backend(service.BackendType.EVENTLET)
from oslo_log import log as logging
LOG = logging.getLogger(__name__)
LOG.info("Service is starting with Eventlet based service backend")
else:
# We asked not to monkey patch so we will run in native threading mode
import oslo_service.backend as service
# NOTE(gibi): This will raise if the backend is already initialized
# with Eventlet
service.init_backend(service.BackendType.THREADING)
# NOTE(gibi): We were asked not to monkey patch. Let's enforce it by
# removing the possibility to monkey_patch accidentally
def poison(*args, **kwargs):
raise RuntimeError(
"The service is started with native threading via "
"OS_NOVA_DISABLE_EVENTLET_PATCHING set to '%s', but then the "
"service tried to call eventlet.monkey_patch(). This is a "
"bug."
% os.environ.get('OS_NOVA_DISABLE_EVENTLET_PATCHING', ''))
import eventlet
eventlet.monkey_patch = poison
eventlet.patcher.monkey_patch = poison
from oslo_log import log as logging
LOG = logging.getLogger(__name__)
LOG.warning(
"Service is starting with native threading. This is currently "
"experimental. Do not use it in production.")

4
nova/rpc.py
View File

@@ -25,6 +25,7 @@ import nova.conf
import nova.context
import nova.exception
from nova.i18n import _
from nova import utils
__all__ = [
'init',
@@ -217,10 +218,11 @@ def get_server(target, endpoints, serializer=None):
else:
serializer = RequestContextSerializer(serializer)
access_policy = dispatcher.DefaultRPCAccessPolicy
exc = "threading" if utils.concurrency_mode_threading() else "eventlet"
return messaging.get_rpc_server(TRANSPORT,
target,
endpoints,
executor='eventlet',
executor=exc,
serializer=serializer,
access_policy=access_policy)

23
nova/tests/unit/test_rpc.py
View File

@@ -250,6 +250,29 @@ class TestRPC(test.NoDBTestCase):
access_policy=access_policy)
self.assertEqual('server', server)
@mock.patch(
'nova.utils.concurrency_mode_threading',
new=mock.Mock(return_value=True))
@mock.patch.object(rpc, 'TRANSPORT')
@mock.patch.object(rpc, 'profiler', None)
@mock.patch.object(rpc, 'RequestContextSerializer')
@mock.patch.object(messaging, 'get_rpc_server')
def test_get_server_threading(self, mock_get, mock_ser, mock_TRANSPORT):
ser = mock.Mock()
tgt = mock.Mock()
ends = mock.Mock()
mock_ser.return_value = ser
mock_get.return_value = 'server'
server = rpc.get_server(tgt, ends, serializer='foo')
mock_ser.assert_called_once_with('foo')
access_policy = dispatcher.DefaultRPCAccessPolicy
mock_get.assert_called_once_with(mock_TRANSPORT, tgt, ends,
executor='threading', serializer=ser,
access_policy=access_policy)
self.assertEqual('server', server)
@mock.patch.object(rpc, 'TRANSPORT')
@mock.patch.object(rpc, 'profiler', mock.Mock())
@mock.patch.object(rpc, 'ProfilerRequestContextSerializer')

40
nova/tests/unit/test_utils.py
View File

@@ -14,6 +14,7 @@
import datetime
import hashlib
import os
import threading
from unittest import mock
@@ -26,11 +27,13 @@ from openstack import exceptions as sdk_exc
from oslo_config import cfg
from oslo_context import context as common_context
from oslo_context import fixture as context_fixture
import oslo_service.backend as oslo_backend
from oslo_utils import encodeutils
from oslo_utils import fixture as utils_fixture
from nova import context
from nova import exception
from nova import monkey_patch
from nova.objects import base as obj_base
from nova.objects import instance as instance_obj
from nova.objects import service as service_obj
@@ -1651,3 +1654,40 @@ class ExecutorStatsTestCase(test.NoDBTestCase):
utils.spawn(self._task_finishes).result()
mock_info.assert_not_called()
class OsloServiceBackendSelectionTestCase(test.NoDBTestCase):
def setUp(self):
# NOTE(gibi): We need this as the base test class would trigger
# monkey patching and would prevent us to test the threading code path
self.useFixture(
fixtures.MonkeyPatch(
"nova.monkey_patch._monkey_patch", lambda: True))
super().setUp()
origi = monkey_patch.MONKEY_PATCHED
monkey_patch.MONKEY_PATCHED = False
def reset():
monkey_patch.MONKEY_PATCHED = origi
self.addCleanup(reset)
@mock.patch('oslo_service.backend.init_backend')
def test_eventlet_selected(self, init_backend):
monkey_patch.patch()
init_backend.assert_called_once_with(oslo_backend.BackendType.EVENTLET)
@mock.patch('oslo_service.backend.init_backend')
@mock.patch.dict(os.environ, {"OS_NOVA_DISABLE_EVENTLET_PATCHING": "true"})
def test_threading_selected_monkey_patching_poisoned(self, init_backend):
monkey_patch.patch()
init_backend.assert_called_once_with(
oslo_backend.BackendType.THREADING)
import eventlet
ex = self.assertRaises(RuntimeError, eventlet.monkey_patch)
self.assertEqual(
"The service is started with native threading via "
"OS_NOVA_DISABLE_EVENTLET_PATCHING set to 'true', but then the "
"service tried to call eventlet.monkey_patch(). This is a bug.",
str(ex))

9
releasenotes/notes/threaded-nova-scheduler-dd4649b987f33025.yaml Normal file
View File

@@ -0,0 +1,9 @@
---
features:
- |
The nova-scheduler now can be run in native threading mode instead
of with eventlet. This is an experimental feature that is disabled by
default. Please read the
`concurrency <https://docs.openstack.org/nova/latest/admin/concurrency.html>`__
guide for more details.

2
requirements.txt
View File

@@ -44,7 +44,7 @@ oslo.messaging>=14.1.0 # Apache-2.0
oslo.policy>=4.5.0 # Apache-2.0
oslo.privsep>=2.6.2 # Apache-2.0
oslo.i18n>=5.1.0 # Apache-2.0
oslo.service>=2.8.0 # Apache-2.0
oslo.service[threading]>=4.2.0 # Apache-2.0
rfc3986>=1.2.0 # Apache-2.0
oslo.middleware>=3.31.0 # Apache-2.0
psutil>=3.2.2 # BSD