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# 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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# 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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# http://www.apache.org/licenses/LICENSE-2.0
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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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from nova import flags
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from nova.scheduler import driver
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from nova.scheduler import chance
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flags.DEFINE_integer("max_cores", 16,
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"maximum number of instance cores to allow per host")
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flags.DEFINE_integer("max_gigabytes", 10000,
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"maximum number of volume gigabytes to allow per host")
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flags.DEFINE_integer("max_networks", 1000,
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"maximum number of networks to allow per host")
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class SimpleScheduler(chance.ChanceScheduler):
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"""Implements Naive Scheduler that tries to find least loaded host."""
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def schedule_run_instance(self, context, instance_id, *_args, **_kwargs):
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"""Picks a host that is up and has the fewest running instances."""
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instance_ref = db.instance_get(context, instance_id)
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results = db.service_get_all_compute_sorted(context)
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for result in results:
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(service, instance_cores) = result
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if instance_cores + instance_ref['vcpus'] > FLAGS.max_cores:
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raise driver.NoValidHost("All hosts have too many cores")
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if self.service_is_up(service):
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# NOTE(vish): this probably belongs in the manager, if we
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# can generalize this somehow
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now = datetime.datetime.utcnow()
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db.instance_update(context,
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{'host': service['host'],
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return service['host']
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raise driver.NoValidHost("No hosts found")
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def schedule_create_volume(self, context, volume_id, *_args, **_kwargs):
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"""Picks a host that is up and has the fewest volumes."""
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volume_ref = db.volume_get(context, volume_id)
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results = db.service_get_all_volume_sorted(context)
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for result in results:
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(service, volume_gigabytes) = result
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if volume_gigabytes + volume_ref['size'] > FLAGS.max_gigabytes:
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raise driver.NoValidHost("All hosts have too many gigabytes")
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if self.service_is_up(service):
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# NOTE(vish): this probably belongs in the manager, if we
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# can generalize this somehow
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now = datetime.datetime.utcnow()
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db.volume_update(context,
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{'host': service['host'],
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return service['host']
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raise driver.NoValidHost("No hosts found")
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def schedule_set_network_host(self, context, *_args, **_kwargs):
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"""Picks a host that is up and has the fewest networks."""
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results = db.service_get_all_network_sorted(context)
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for result in results:
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(service, instance_count) = result
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if instance_count >= FLAGS.max_networks:
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raise driver.NoValidHost("All hosts have too many networks")
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if self.service_is_up(service):
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return service['host']
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raise driver.NoValidHost("No hosts found")
added
removed
nova/scheduler/simple.py
