78 lines
3.1 KiB
Python
78 lines
3.1 KiB
Python
# Copyright (c) 2014 Cisco Systems Inc.
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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 oslo_log import log as logging
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from nova.i18n import _
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from nova_solverscheduler.scheduler.solvers import constraints
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CONF = cfg.CONF
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CONF.import_opt('ram_allocation_ratio', 'nova.scheduler.filters.ram_filter')
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LOG = logging.getLogger(__name__)
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class RamConstraint(constraints.BaseLinearConstraint):
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"""Constraint of the total ram demand acceptable on each host."""
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def _get_ram_allocation_ratio(self, host_state, filter_properties):
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return CONF.ram_allocation_ratio
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def get_constraint_matrix(self, hosts, filter_properties):
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num_hosts = len(hosts)
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num_instances = filter_properties.get('num_instances')
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constraint_matrix = [[True for j in xrange(num_instances)]
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for i in xrange(num_hosts)]
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# get requested ram
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instance_type = filter_properties.get('instance_type') or {}
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requested_ram = instance_type.get('memory_mb', 0)
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if 'memory_mb' not in instance_type:
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LOG.warn(_("No information about requested instances\' RAM size "
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"was found, default value (0) is used."))
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if requested_ram <= 0:
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LOG.warn(_("RamConstraint is skipped because requested "
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"instance RAM size is 0 or invalid."))
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return constraint_matrix
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for i in xrange(num_hosts):
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ram_allocation_ratio = self._get_ram_allocation_ratio(
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hosts[i], filter_properties)
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# get available ram
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free_ram_mb = hosts[i].free_ram_mb
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total_usable_ram_mb = hosts[i].total_usable_ram_mb
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memory_mb_limit = total_usable_ram_mb * ram_allocation_ratio
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used_ram_mb = total_usable_ram_mb - free_ram_mb
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usable_ram = memory_mb_limit - used_ram_mb
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acceptable_num_instances = int(usable_ram / requested_ram)
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if acceptable_num_instances < num_instances:
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inacceptable_num = num_instances - acceptable_num_instances
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constraint_matrix[i] = (
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[True for j in xrange(acceptable_num_instances)] +
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[False for j in xrange(inacceptable_num)])
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LOG.debug(_("%(host)s can accept %(num)s requested instances "
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"according to RamConstraint."),
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{'host': hosts[i],
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'num': acceptable_num_instances})
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hosts[i].limits['memory_mb'] = memory_mb_limit
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return constraint_matrix
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