nova-solver-scheduler/nova/scheduler/solvers/linearconstraints/active_host_constraint.py

86 lines
3.6 KiB
Python

# Copyright (c) 2014 Cisco Systems Inc.
# 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.
from oslo.config import cfg
from nova.openstack.common.gettextutils import _
from nova.openstack.common import log as logging
from nova.scheduler.solvers import linearconstraints
from nova import servicegroup
CONF = cfg.CONF
LOG = logging.getLogger(__name__)
class ActiveHostConstraint(linearconstraints.BaseLinearConstraint):
"""Constraint that only allows active hosts to be selected."""
# The linear constraint should be formed as:
# coeff_matrix * var_matrix' (operator) (constants)
# where (operator) is ==, >, >=, <, <=, !=, etc.
# For convenience, the (constants) is merged into left-hand-side,
# thus the right-hand-side is 0.
def __init__(self, variables, hosts, instance_uuids, request_spec,
filter_properties):
self.servicegroup_api = servicegroup.API()
[self.num_hosts, self.num_instances] = self._get_host_instance_nums(
hosts, instance_uuids, request_spec)
def _get_host_instance_nums(self, hosts, instance_uuids, request_spec):
"""This method calculates number of hosts and instances."""
num_hosts = len(hosts)
if instance_uuids:
num_instances = len(instance_uuids)
else:
num_instances = request_spec.get('num_instances', 1)
return [num_hosts, num_instances]
def get_coefficient_vectors(self, variables, hosts, instance_uuids,
request_spec, filter_properties):
"""Calculate the coeffivient vectors."""
# Coefficients are 0 for active hosts and 1 otherwise
coefficient_matrix = []
for host in hosts:
service = host.service
if service['disabled'] or not self.servicegroup_api.service_is_up(
service):
coefficient_matrix.append([1 for j in range(
self.num_instances)])
LOG.debug(_("%s is not active") % host.host)
else:
coefficient_matrix.append([0 for j in range(
self.num_instances)])
LOG.debug(_("%s is ok") % host.host)
return coefficient_matrix
def get_variable_vectors(self, variables, hosts, instance_uuids,
request_spec, filter_properties):
"""Reorganize the variables."""
# The variable_matrix[i,j] denotes the relationship between
# host[i] and instance[j].
variable_matrix = []
variable_matrix = [[variables[i][j] for j in range(
self.num_instances)] for i in range(self.num_hosts)]
return variable_matrix
def get_operations(self, variables, hosts, instance_uuids, request_spec,
filter_properties):
"""Set operations for each constraint function."""
# Operations are '=='.
operations = [(lambda x: x == 0) for i in range(self.num_hosts)]
return operations