55 lines
1.9 KiB
Python
55 lines
1.9 KiB
Python
# Copyright (c) 2012-2013 Rackspace Hosting
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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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"""
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Weigh cells by memory needed in a way that spreads instances.
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"""
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from oslo.config import cfg
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from nova.cells import weights
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ram_weigher_opts = [
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cfg.FloatOpt('ram_weight_multiplier',
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default=10.0,
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help='Multiplier used for weighing ram. Negative '
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'numbers mean to stack vs spread.'),
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]
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CONF = cfg.CONF
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CONF.register_opts(ram_weigher_opts, group='cells')
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class RamByInstanceTypeWeigher(weights.BaseCellWeigher):
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"""Weigh cells by instance_type requested."""
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def weight_multiplier(self):
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return CONF.cells.ram_weight_multiplier
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def _weigh_object(self, cell, weight_properties):
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"""
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Use the 'ram_free' for a particular instance_type advertised from a
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child cell's capacity to compute a weight. We want to direct the
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build to a cell with a higher capacity. Since higher weights win,
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we just return the number of units available for the instance_type.
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"""
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request_spec = weight_properties['request_spec']
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instance_type = request_spec['instance_type']
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memory_needed = instance_type['memory_mb']
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ram_free = cell.capacities.get('ram_free', {})
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units_by_mb = ram_free.get('units_by_mb', {})
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return units_by_mb.get(str(memory_needed), 0)
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