134 lines
		
	
	
		
			6.3 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			134 lines
		
	
	
		
			6.3 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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Simple Scheduler
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"""
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from nova import db
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from nova import flags
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from nova import utils
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from nova.scheduler import driver
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from nova.scheduler import chance
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FLAGS = flags.FLAGS
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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_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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        if (instance_ref['availability_zone']
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            and ':' in instance_ref['availability_zone']
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            and context.is_admin):
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            zone, _x, host = instance_ref['availability_zone'].partition(':')
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            service = db.service_get_by_args(context.elevated(), host,
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                                             'nova-compute')
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            if not self.service_is_up(service):
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                raise driver.WillNotSchedule(_("Host %s is not alive") % host)
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            # TODO(vish): this probably belongs in the manager, if we
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            #             can generalize this somehow
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            now = utils.utcnow()
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            db.instance_update(context, instance_id, {'host': host,
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                                                      'scheduled_at': now})
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            return host
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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 = utils.utcnow()
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                db.instance_update(context,
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                                   instance_id,
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                                   {'host': service['host'],
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                                    'scheduled_at': now})
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                return service['host']
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        raise driver.NoValidHost(_("Scheduler was unable to locate a host"
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                                   " for this request. Is the appropriate"
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                                   " service running?"))
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    def schedule_run_instance(self, context, instance_id, *_args, **_kwargs):
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        return self._schedule_instance(context, instance_id, *_args, **_kwargs)
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    def schedule_start_instance(self, context, instance_id, *_args, **_kwargs):
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        return self._schedule_instance(context, instance_id, *_args, **_kwargs)
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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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        if (volume_ref['availability_zone']
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            and ':' in volume_ref['availability_zone']
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            and context.is_admin):
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            zone, _x, host = volume_ref['availability_zone'].partition(':')
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            service = db.service_get_by_args(context.elevated(), host,
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                                             'nova-volume')
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            if not self.service_is_up(service):
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                raise driver.WillNotSchedule(_("Host %s not available") % host)
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            # TODO(vish): this probably belongs in the manager, if we
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            #             can generalize this somehow
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            now = utils.utcnow()
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            db.volume_update(context, volume_id, {'host': host,
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                                                  'scheduled_at': now})
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            return host
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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 "
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                                           "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 = utils.utcnow()
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                db.volume_update(context,
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                                 volume_id,
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                                 {'host': service['host'],
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                                  'scheduled_at': now})
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                return service['host']
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        raise driver.NoValidHost(_("Scheduler was unable to locate a host"
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                                   " for this request. Is the appropriate"
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                                   " service running?"))
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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(_("Scheduler was unable to locate a host"
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                                   " for this request. Is the appropriate"
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                                   " service running?"))
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