7e61cb9761
Changed help message for allocated_capacity_weight_multiplier to correctly show that positive weights are needed to stack. Also changed wording to indicate free and allocated capacity for the respective values. Change-Id: I84120d3598cde014eaf3fef5998dea5b69439240 Closes-bug: #1460568
138 lines
5.4 KiB
Python
138 lines
5.4 KiB
Python
# Copyright (c) 2013 eBay Inc.
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# Copyright (c) 2012 OpenStack Foundation
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# Copyright (c) 2015 EMC Corporation
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#
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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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Weighers that weigh hosts by their capacity, including following two
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weighers:
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1. Capacity Weigher. Weigh hosts by their virtual or actual free capacity.
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For thin provisioning, weigh hosts by their virtual free capacity calculated
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by the total capacity multiplied by the max over subscription ratio and
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subtracting the provisioned capacity; Otherwise, weigh hosts by their actual
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free capacity, taking into account the reserved space.
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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 'capacity_weight_multiplier' option to a negative
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number and the weighing has the opposite effect of the default.
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2. Allocated Capacity Weigher. Weigh hosts by their allocated capacity.
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The default behavior is to place new volume to the host allocated the least
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space. This weigher is intended to simulate the behavior of SimpleScheduler.
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If you prefer to place volumes to host allocated the most space, you can
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set the 'allocated_capacity_weight_multiplier' option to a positive number
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and the weighing has the opposite effect of the default.
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"""
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import math
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from oslo_config import cfg
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from cinder.scheduler import weights
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from cinder import utils
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capacity_weight_opts = [
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cfg.FloatOpt('capacity_weight_multiplier',
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default=1.0,
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help='Multiplier used for weighing free capacity. '
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'Negative numbers mean to stack vs spread.'),
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cfg.FloatOpt('allocated_capacity_weight_multiplier',
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default=-1.0,
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help='Multiplier used for weighing allocated capacity. '
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'Positive numbers mean to stack vs spread.'),
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]
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CONF = cfg.CONF
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CONF.register_opts(capacity_weight_opts)
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OFFSET_MIN = 10000
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OFFSET_MULT = 100
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class CapacityWeigher(weights.BaseHostWeigher):
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def weight_multiplier(self):
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"""Override the weight multiplier."""
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return CONF.capacity_weight_multiplier
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def weigh_objects(self, weighed_obj_list, weight_properties):
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"""Override the weigh objects.
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This override calls the parent to do the weigh objects and then
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replaces any infinite weights with a value that is a multiple of the
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delta between the min and max values.
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NOTE(jecarey): the infinite weight value is only used when the
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smallest value is being favored (negative multiplier). When the
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largest weight value is being used a weight of -1 is used instead.
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See _weigh_object method.
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"""
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tmp_weights = super(weights.BaseHostWeigher, self).weigh_objects(
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weighed_obj_list, weight_properties)
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if math.isinf(self.maxval):
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# NOTE(jecarey): if all weights were infinite then parent
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# method returns 0 for all of the weights. Thus self.minval
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# cannot be infinite at this point
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copy_weights = [w for w in tmp_weights if not math.isinf(w)]
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self.maxval = max(copy_weights)
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offset = (self.maxval - self.minval) * OFFSET_MULT
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self.maxval += OFFSET_MIN if offset == 0.0 else offset
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tmp_weights = [self.maxval if math.isinf(w) else w
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for w in tmp_weights]
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return tmp_weights
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def _weigh_object(self, host_state, weight_properties):
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"""Higher weights win. We want spreading to be the default."""
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free_space = host_state.free_capacity_gb
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total_space = host_state.total_capacity_gb
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if (free_space == 'infinite' or free_space == 'unknown' or
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total_space == 'infinite' or total_space == 'unknown'):
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# (zhiteng) 'infinite' and 'unknown' are treated the same
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# here, for sorting purpose.
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# As a partial fix for bug #1350638, 'infinite' and 'unknown' are
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# given the lowest weight to discourage driver from report such
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# capacity anymore.
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free = -1 if CONF.capacity_weight_multiplier > 0 else float('inf')
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else:
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free = utils.calculate_virtual_free_capacity(
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total_space,
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free_space,
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host_state.provisioned_capacity_gb,
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host_state.thin_provisioning_support,
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host_state.max_over_subscription_ratio,
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host_state.reserved_percentage)
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return free
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class AllocatedCapacityWeigher(weights.BaseHostWeigher):
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def weight_multiplier(self):
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"""Override the weight multiplier."""
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return CONF.allocated_capacity_weight_multiplier
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def _weigh_object(self, host_state, weight_properties):
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# Higher weights win. We want spreading (choose host with lowest
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# allocated_capacity first) to be the default.
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allocated_space = host_state.allocated_capacity_gb
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return allocated_space
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