gantt/nova/scheduler/chance.py
Mark McLoughlin 7e9566cf08 Use CONF.import_opt() for nova.config opts
The only reason for importing nova.config now is where one of the
options defined in that file is needed. Rather than importing
nova.config using an import statement, use CONF.import_opt() so
that it is clear which option we actually require.

In future, we will move many options out of nova.config so many
of these import_opt() calls will either go away or cause a module
other than nova.config to be imported.

Change-Id: I0646efddecdf2530903afd50c1f4364cb1d5dce1
2012-11-20 00:04:49 +00:00

96 lines
4.0 KiB
Python

# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright (c) 2010 OpenStack, LLC.
# 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 nova import exception
from nova.openstack.common import cfg
from nova.scheduler import driver
CONF = cfg.CONF
CONF.import_opt('compute_topic', 'nova.config')
class ChanceScheduler(driver.Scheduler):
"""Implements Scheduler as a random node selector."""
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
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 hosts[int(random.random() * len(hosts))]
def schedule_run_instance(self, context, request_spec,
admin_password, injected_files,
requested_networks, is_first_time,
filter_properties):
"""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)
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)
def schedule_prep_resize(self, context, image, request_spec,
filter_properties, instance, instance_type,
reservations):
"""Select a target for resize."""
host = self._schedule(context, CONF.compute_topic, request_spec,
filter_properties)
self.compute_rpcapi.prep_resize(context, image, instance,
instance_type, host, reservations)