72 lines
2.6 KiB
Python
72 lines
2.6 KiB
Python
# 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 oslo.config import cfg
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from manila import exception
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from manila.scheduler import driver
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CONF = cfg.CONF
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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, **kwargs):
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"""Filter a list of hosts based on request_spec."""
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filter_properties = kwargs.get('filter_properties', {})
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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, **kwargs):
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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, **kwargs)
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if not hosts:
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msg = _("Could not find another host")
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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_create_share(self, context, request_spec, filter_properties):
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"""Picks a host that is up at random."""
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topic = CONF.share_topic
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host = self._schedule(context, topic, request_spec,
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filter_properties=filter_properties)
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share_id = request_spec['share_id']
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snapshot_id = request_spec['snapshot_id']
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updated_share = driver.share_update_db(context, share_id, host)
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self.share_rpcapi.create_share(context, updated_share, host,
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request_spec,
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filter_properties,
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snapshot_id)
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