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OpenStack Study: chance.py**** CubicPower OpenStack Study ****
# 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. """ Chance (Random) Scheduler implementation """ import random from oslo.config import cfg from nova.compute import rpcapi as compute_rpcapi from nova import exception from nova.openstack.common.gettextutils import _ from nova.scheduler import driver CONF = cfg.CONF CONF.import_opt('compute_topic', 'nova.compute.rpcapi')
**** CubicPower OpenStack Study **** class ChanceScheduler(driver.Scheduler): """Implements Scheduler as a random node selector."""
**** CubicPower OpenStack Study **** def __init__(self, *args, **kwargs): super(ChanceScheduler, self).__init__(*args, **kwargs) self.compute_rpcapi = compute_rpcapi.ComputeAPI()
**** CubicPower OpenStack Study **** def _filter_hosts(self, request_spec, hosts, filter_properties): """Filter a list of hosts based on request_spec.""" ignore_hosts = filter_properties.get('ignore_hosts', []) hosts = [host for host in hosts if host not in ignore_hosts] return hosts
**** CubicPower OpenStack Study **** def _schedule(self, context, topic, request_spec, filter_properties): """Picks a host that is up at random.""" elevated = context.elevated() hosts = self.hosts_up(elevated, topic) if not hosts: msg = _("Is the appropriate service running?") raise exception.NoValidHost(reason=msg) hosts = self._filter_hosts(request_spec, hosts, filter_properties) if not hosts: msg = _("Could not find another compute") raise exception.NoValidHost(reason=msg) return random.choice(hosts)
**** CubicPower OpenStack Study **** def select_destinations(self, context, request_spec, filter_properties): """Selects random destinations.""" num_instances = request_spec['num_instances'] # NOTE(timello): Returns a list of dicts with 'host', 'nodename' and # 'limits' as keys for compatibility with filter_scheduler. dests = [] for i in range(num_instances): host = self._schedule(context, CONF.compute_topic, request_spec, filter_properties) host_state = dict(host=host, nodename=None, limits=None) dests.append(host_state) if len(dests) < num_instances: raise exception.NoValidHost(reason='') return dests
**** CubicPower OpenStack Study **** def schedule_run_instance(self, context, request_spec, admin_password, injected_files, requested_networks, is_first_time, filter_properties, legacy_bdm_in_spec): """Create and run an instance or instances.""" instance_uuids = request_spec.get('instance_uuids') for num, instance_uuid in enumerate(instance_uuids): request_spec['instance_properties']['launch_index'] = num try: host = self._schedule(context, CONF.compute_topic, request_spec, filter_properties) updated_instance = driver.instance_update_db(context, instance_uuid) self.compute_rpcapi.run_instance(context, instance=updated_instance, host=host, requested_networks=requested_networks, injected_files=injected_files, admin_password=admin_password, is_first_time=is_first_time, request_spec=request_spec, filter_properties=filter_properties, legacy_bdm_in_spec=legacy_bdm_in_spec) except Exception as ex: # NOTE(vish): we don't reraise the exception here to make sure # that all instances in the request get set to # error properly driver.handle_schedule_error(context, ex, instance_uuid, request_spec)
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