86 lines
3.7 KiB
Python
86 lines
3.7 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 nova.scheduler.solvers import linearconstraints
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CONF = cfg.CONF
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CONF.import_opt('disk_allocation_ratio', 'nova.scheduler.filters.disk_filter')
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class MaxDiskAllocationPerHostConstraint(
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linearconstraints.ResourceAllocationConstraint):
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"""Constraint of the maximum total disk demand acceptable on each host."""
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# The linear constraint should be formed as:
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# coeff_vectors * var_vectors' (operator) (constants)
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# where (operator) is ==, >, >=, <, <=, !=, etc.
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# For convenience, the (constants) is merged into left-hand-side,
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# thus the right-hand-side is 0.
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def get_coefficient_vectors(self, variables, hosts, instance_uuids,
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request_spec, filter_properties):
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# Give demand as coefficient for each variable and -supply as
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# constant in each constraint.
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demand = [self._get_required_disk_mb(filter_properties)
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for j in range(self.num_instances)]
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supply = [self._get_usable_disk_mb(hosts[i])
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for i in range(self.num_hosts)]
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coefficient_vectors = [demand + [-supply[i]]
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for i in range(self.num_hosts)]
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return coefficient_vectors
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def get_variable_vectors(self, variables, hosts, instance_uuids,
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request_spec, filter_properties):
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# The variable_vectors[i,j] denotes the relationship between host[i]
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# and instance[j].
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variable_vectors = []
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variable_vectors = [[variables[i][j]
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for j in range(self.num_instances)]
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+ [1] for i in range(self.num_hosts)]
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return variable_vectors
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def get_operations(self, variables, hosts, instance_uuids, request_spec,
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filter_properties):
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# Operations are '<='.
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operations = [(lambda x: x <= 0) for i in range(self.num_hosts)]
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return operations
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def _get_usable_disk_mb(self, host_state):
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"""This method returns the usable disk in mb for the given host.
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Takes into account the disk allocation ratio (virtual disk to
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physical disk allocation ratio)
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"""
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free_disk_mb = host_state.free_disk_mb
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total_usable_disk_mb = host_state.total_usable_disk_gb * 1024
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disk_mb_limit = total_usable_disk_mb * CONF.disk_allocation_ratio
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used_disk_mb = total_usable_disk_mb - free_disk_mb
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usable_disk_mb = disk_mb_limit - used_disk_mb
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return usable_disk_mb
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def _get_required_disk_mb(self, filter_properties):
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"""This method returns the required disk in mb from
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the given filter_properties dictionary object.
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"""
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requested_disk_mb = 0
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instance_type = filter_properties.get('instance_type')
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if instance_type is not None:
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requested_disk_mb = (1024 * (instance_type.get('root_gb', 0) +
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instance_type.get('ephemeral_gb', 0)) +
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instance_type.get('swap', 0))
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return requested_disk_mb
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