nova/nova/scheduler/driver.py

67 lines
2.3 KiB
Python

# Copyright (c) 2010 OpenStack Foundation
# Copyright 2010 United States Government as represented by the
# Administrator of the National Aeronautics and Space Administration.
# 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.
"""
Scheduler base class that all Schedulers should inherit from
"""
from oslo_config import cfg
from oslo_utils import importutils
from nova import db
from nova.i18n import _
from nova import servicegroup
scheduler_driver_opts = [
cfg.StrOpt('scheduler_host_manager',
default='nova.scheduler.host_manager.HostManager',
help='The scheduler host manager class to use'),
]
CONF = cfg.CONF
CONF.register_opts(scheduler_driver_opts)
class Scheduler(object):
"""The base class that all Scheduler classes should inherit from."""
def __init__(self):
self.host_manager = importutils.import_object(
CONF.scheduler_host_manager)
self.servicegroup_api = servicegroup.API()
def run_periodic_tasks(self, context):
"""Manager calls this so drivers can perform periodic tasks."""
pass
def hosts_up(self, context, topic):
"""Return the list of hosts that have a running service for topic."""
services = db.service_get_all_by_topic(context, topic)
return [service['host']
for service in services
if self.servicegroup_api.service_is_up(service)]
def select_destinations(self, context, request_spec, filter_properties):
"""Must override select_destinations method.
:return: A list of dicts with 'host', 'nodename' and 'limits' as keys
that satisfies the request_spec and filter_properties.
"""
msg = _("Driver must implement select_destinations")
raise NotImplementedError(msg)