e7152eef7b
This changes select_destinations() on the scheduler side to optionally return Selection objects and alternates. The RPC signature doesn't change in this patch, though, so everything on the conductor side remains unchanged. The next patch in the series will make the actual RPC change. Blueprint: return-alternate-hosts Change-Id: I03b95a2106624c2ea24835814ca38e954ec7a997
71 lines
2.4 KiB
Python
71 lines
2.4 KiB
Python
# Copyright (c) 2010 OpenStack Foundation
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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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Scheduler base class that all Schedulers should inherit from
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"""
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import abc
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import six
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from stevedore import driver
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import nova.conf
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from nova import objects
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from nova import servicegroup
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CONF = nova.conf.CONF
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@six.add_metaclass(abc.ABCMeta)
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class Scheduler(object):
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"""The base class that all Scheduler classes should inherit from."""
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USES_ALLOCATION_CANDIDATES = True
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"""Indicates that the scheduler driver calls the Placement API for
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allocation candidates and uses those allocation candidates in its
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decision-making.
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"""
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def __init__(self):
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self.host_manager = driver.DriverManager(
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"nova.scheduler.host_manager",
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CONF.scheduler.host_manager,
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invoke_on_load=True).driver
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self.servicegroup_api = servicegroup.API()
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def run_periodic_tasks(self, context):
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"""Manager calls this so drivers can perform periodic tasks."""
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pass
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def hosts_up(self, context, topic):
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"""Return the list of hosts that have a running service for topic."""
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services = objects.ServiceList.get_by_topic(context, topic)
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return [service.host
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for service in services
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if self.servicegroup_api.service_is_up(service)]
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@abc.abstractmethod
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def select_destinations(self, context, spec_obj, instance_uuids,
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alloc_reqs_by_rp_uuid, provider_summaries,
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allocation_request_version=None, return_alternates=False):
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"""Returns a list of lists of Selection objects that have been chosen
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by the scheduler driver, one for each requested instance.
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"""
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return []
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