96 lines
4.0 KiB
Python
96 lines
4.0 KiB
Python
# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright (c) 2010 OpenStack, LLC.
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# Copyright 2010 United States Government as represented by the
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# Administrator of the National Aeronautics and Space Administration.
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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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"""
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Chance (Random) Scheduler implementation
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"""
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import random
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from nova import exception
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from nova.openstack.common import cfg
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from nova.scheduler import driver
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CONF = cfg.CONF
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CONF.import_opt('compute_topic', 'nova.config')
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class ChanceScheduler(driver.Scheduler):
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"""Implements Scheduler as a random node selector."""
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def _filter_hosts(self, request_spec, hosts, filter_properties):
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"""Filter a list of hosts based on request_spec."""
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ignore_hosts = filter_properties.get('ignore_hosts', [])
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hosts = [host for host in hosts if host not in ignore_hosts]
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return hosts
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def _schedule(self, context, topic, request_spec, filter_properties):
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"""Picks a host that is up at random."""
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elevated = context.elevated()
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hosts = self.hosts_up(elevated, topic)
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if not hosts:
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msg = _("Is the appropriate service running?")
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raise exception.NoValidHost(reason=msg)
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hosts = self._filter_hosts(request_spec, hosts, filter_properties)
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if not hosts:
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msg = _("Could not find another compute")
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raise exception.NoValidHost(reason=msg)
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return hosts[int(random.random() * len(hosts))]
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def schedule_run_instance(self, context, request_spec,
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admin_password, injected_files,
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requested_networks, is_first_time,
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filter_properties):
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"""Create and run an instance or instances."""
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instance_uuids = request_spec.get('instance_uuids')
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for num, instance_uuid in enumerate(instance_uuids):
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request_spec['instance_properties']['launch_index'] = num
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try:
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host = self._schedule(context, CONF.compute_topic,
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request_spec, filter_properties)
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updated_instance = driver.instance_update_db(context,
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instance_uuid)
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self.compute_rpcapi.run_instance(context,
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instance=updated_instance, host=host,
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requested_networks=requested_networks,
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injected_files=injected_files,
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admin_password=admin_password,
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is_first_time=is_first_time,
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request_spec=request_spec,
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filter_properties=filter_properties)
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except Exception as ex:
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# NOTE(vish): we don't reraise the exception here to make sure
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# that all instances in the request get set to
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# error properly
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driver.handle_schedule_error(context, ex, instance_uuid,
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request_spec)
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def schedule_prep_resize(self, context, image, request_spec,
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filter_properties, instance, instance_type,
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reservations):
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"""Select a target for resize."""
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host = self._schedule(context, CONF.compute_topic, request_spec,
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filter_properties)
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self.compute_rpcapi.prep_resize(context, image, instance,
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instance_type, host, reservations)
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