<div dir="ltr"><div><div>I am in the process of implementing a custom weigher class. I have created a weigher that prefers hosts which do not have other instances in the same group (think GroupAntiAffinityFilter but for weight). <br>
<br></div>Here is the code for the class:<br><br># Copyright (c) 2011 OpenStack Foundation<br># All Rights Reserved.<br>#<br># Licensed under the Apache License, Version 2.0 (the "License"); you may<br># not use this file except in compliance with the License. You may obtain<br>
# a copy of the License at<br>#<br># <a href="http://www.apache.org/licenses/LICENSE-2.0">http://www.apache.org/licenses/LICENSE-2.0</a><br>#<br># Unless required by applicable law or agreed to in writing, software<br>
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT<br># WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the<br># License for the specific language governing permissions and limitations<br>
<br>"""<br>AntiAffinityWeigher. Weigh hosts by whether or not they have another host in the same group.<br><br>"""<br><br>from oslo.config import cfg<br><br>from nova import db<br>from nova.openstack.common.gettextutils import _<br>
from nova.scheduler import weights<br>from nova.scheduler import filters<br>from nova.openstack.common import log as logging<br><br>LOG = logging.getLogger(__name__)<br><br>anti_affinity_weight_opts = [<br> cfg.FloatOpt('antiAffinityWeigher_Multiplier',<br>
default=1000.0,<br> help='Multiplier used for weighing hosts. Negative '<br> 'numbers mean to stack vs spread.'),<br>]<br><br>CONF = cfg.CONF<br>
CONF.register_opts(anti_affinity_weight_opts)<br><br><br>class AntiAffinityWeigher(weights.BaseHostWeigher):<br> def _weight_multiplier(self):<br> """Override the weight multiplier."""<br>
return CONF.antiAffinityWeigher_Multiplier<br><br> def _weigh_object(self, host_state, weight_properties):<br> group_hosts = weight_properties.get('group_hosts') or []<br> LOG.debug(_("Group anti affinity Weigher: check if %(host)s not "<br>
"in %(configured)s"), {'host': host_state.host,<br> 'configured': group_hosts})<br> if group_hosts:<br> return group_hosts.amount() * 100000<br><br> # No groups configured<br>
return 0<br><br><br></div><div>I know the python is at least close to correct because the scheduler service wouldn't even restart until it was. After I got the bugs worked out of the module, I added modified the /etc/nova/nova.conf file to have the custom weigher like so: <br>
scheduler_weight_classes=nova.scheduler.weights.all_weighers,nova.scheduler.AntiAffinityWeigher<br><br></div><div>After restarting the scheduler service I get the following error in the nova logs:<br><178>Aug 1 16:46:11 node-25 nova-nova CRITICAL: Class AntiAffinityWeigher cannot be found (['Traceback (most recent call last):\n', ' File "/usr/lib/python2.6/site-packages/nova/openstack/common/importutils.py", line 31, in import_class\n return getattr(sys.modules[mod_str], class_str)\n', "AttributeError: 'module' object has no attribute 'AntiAffinityWeigher'\n"])<br>
Traceback (most recent call last):<br> File "/usr/bin/nova-scheduler", line 10, in <module><br> sys.exit(main())<br> File "/usr/lib/python2.6/site-packages/nova/cmd/scheduler.py", line 39, in main<br>
topic=CONF.scheduler_topic)<br> File "/usr/lib/python2.6/site-packages/nova/service.py", line 257, in create<br> db_allowed=db_allowed)<br> File "/usr/lib/python2.6/site-packages/nova/service.py", line 139, in __init__<br>
self.manager = manager_class(host=self.host, *args, **kwargs)<br> File "/usr/lib/python2.6/site-packages/nova/scheduler/manager.py", line 65, in __init__<br> self.driver = importutils.import_object(scheduler_driver)<br>
File "/usr/lib/python2.6/site-packages/nova/openstack/common/importutils.py", line 40, in import_object<br> return import_class(import_str)(*args, **kwargs)<br> File "/usr/lib/python2.6/site-packages/nova/scheduler/filter_scheduler.py", line 59, in __init__<br>
super(FilterScheduler, self).__init__(*args, **kwargs)<br> File "/usr/lib/python2.6/site-packages/nova/scheduler/driver.py", line 103, in __init__<br> CONF.scheduler_host_manager)<br> File "/usr/lib/python2.6/site-packages/nova/openstack/common/importutils.py", line 40, in import_object<br>
return import_class(import_str)(*args, **kwargs)<br> File "/usr/lib/python2.6/site-packages/nova/scheduler/host_manager.py", line 297, in __init__<br> CONF.scheduler_weight_classes)<br> File "/usr/lib/python2.6/site-packages/nova/loadables.py", line 105, in get_matching_classes<br>
obj = importutils.import_class(cls_name)<br> File "/usr/lib/python2.6/site-packages/nova/openstack/common/importutils.py", line 35, in import_class<br> traceback.format_exception(*sys.exc_info())))<br>ImportError: Class AntiAffinityWeigher cannot be found (['Traceback (most recent call last):\n', ' File "/usr/lib/python2.6/site-packages/nova/openstack/common/importutils.py", line 31, in import_class\n return getattr(sys.modules[mod_str], class_str)\n', "AttributeError: 'module' object has no attribute 'AntiAffinityWeigher'\n"])<br>
<br><br><br></div><div>I have also tried a few different naming conventions such as "AntiAffinityWeigher.AntiAffinityWeigher" and "myWeigher.AntiAffinityWeigher" to no avail. <br><br></div><div>Any help would be greatly appreciated.<br>
<br>Thanks,<br>Danny<br></div></div>