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<div class="moz-cite-prefix">Le 01/08/2014 18:46, Danny Beutler a
écrit :<br>
</div>
<blockquote
cite="mid:CABpu9YeCa8jshSnPsR371_uCP8o-xdqQD_0GBCCw+Zm9t0intw@mail.gmail.com"
type="cite">
<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 moz-do-not-send="true"
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>
</div>
</div>
</blockquote>
<br>
Sure, just look at the traceback, the exception is really explicite.
When giving in the config the name of the new weighter, you just
missed a submodule in nova.scheduler.<br>
<br>
Correct it, it's not nova.scheduler.AntiAffinityWeigher :-)<br>
<br>
<br>
Don't hesitate to provide this change upstream, please so we could
review it.<br>
<br>
-Sylvain<br>
<br>
<blockquote
cite="mid:CABpu9YeCa8jshSnPsR371_uCP8o-xdqQD_0GBCCw+Zm9t0intw@mail.gmail.com"
type="cite">
<div dir="ltr">
<div>Thanks,<br>
Danny<br>
</div>
</div>
<br>
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