nova/nova/cells/weights/weight_offset.py

48 lines
1.5 KiB
Python

# Copyright (c) 2012-2013 Rackspace Hosting
# All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
"""
Weigh cells by their weight_offset in the DB. Cells with higher
weight_offsets in the DB will be preferred.
"""
from oslo.config import cfg
from nova.cells import weights
weigher_opts = [
cfg.FloatOpt('offset_weight_multiplier',
default=1.0,
help='Multiplier used to weigh offset weigher.'),
]
CONF = cfg.CONF
CONF.register_opts(weigher_opts, group='cells')
class WeightOffsetWeigher(weights.BaseCellWeigher):
"""
Weight cell by weight_offset db field.
Originally designed so you can set a default cell by putting
its weight_offset to 999999999999999 (highest weight wins)
"""
def weight_multiplier(self):
return CONF.cells.offset_weight_multiplier
def _weigh_object(self, cell, weight_properties):
"""Returns whatever was in the DB for weight_offset."""
return cell.db_info.get('weight_offset', 0)