56 lines
2.0 KiB
Python
56 lines
2.0 KiB
Python
# Copyright (c) 2014 OpenStack Foundation
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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from oslo_config import cfg
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from cinder import db
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from cinder.scheduler import weights
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volume_number_weight_opts = [
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cfg.FloatOpt('volume_number_multiplier',
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default=-1.0,
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help='Multiplier used for weighing volume number. '
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'Negative numbers mean to spread vs stack.'),
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]
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CONF = cfg.CONF
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CONF.register_opts(volume_number_weight_opts)
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class VolumeNumberWeigher(weights.BaseHostWeigher):
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"""Weigher that weighs hosts by volume number in backends.
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The default is to spread volumes across all hosts evenly. If you prefer
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stacking, you can set the ``volume_number_multiplier`` option to a positive
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number and the weighing has the opposite effect of the default.
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"""
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def weight_multiplier(self):
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"""Override the weight multiplier."""
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return CONF.volume_number_multiplier
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def _weigh_object(self, host_state, weight_properties):
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"""Less volume number weights win.
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We want spreading to be the default.
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"""
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context = weight_properties['context']
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context = context.elevated()
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volume_number = db.volume_data_get_for_host(context=context,
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host=host_state.host,
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count_only=True)
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return volume_number
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