952de1af0b
This implements a [hosts] <=> [images] mapping in the simple scheduler that partitions your host resources into the part that services a particular image set, and the general cloud. This is useful, for example, if you want to specify a set of hosts to run utility VMs (cloudpipe, bastion, etc) that you don't want consuming resources from your generally available pool. When specifying a host with --isolated_hosts flags (comma-separated list) those hosts will only run the images specified in --isolated_images, and will not run any other images. The isolated images will not run on any other hosts. You can specify --skip_isolated_core_check to allow overcommitting of the isolated hosts. This allows utility vms that are not cpu bound to avoid the resource cheks the scheduler usually performs (based off of --max_cores). Change-Id: Ib2db5a605cb7560a169af9ff2a6dadb649da9c1d
161 lines
7.2 KiB
Python
161 lines
7.2 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 exception
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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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flags.DEFINE_string('default_schedule_zone', None,
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'zone to use when user doesnt specify one')
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flags.DEFINE_list('isolated_images', [], 'Images to run on isolated host')
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flags.DEFINE_list('isolated_hosts', [], 'Host reserved for specific images')
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flags.DEFINE_boolean('skip_isolated_core_check', True,
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'Allow overcommitting vcpus on isolated hosts')
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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_opts, *_args, **_kwargs):
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"""Picks a host that is up and has the fewest running instances."""
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elevated = context.elevated()
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availability_zone = instance_opts.get('availability_zone')
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zone, host = FLAGS.default_schedule_zone, None
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if availability_zone:
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zone, _x, host = availability_zone.partition(':')
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if host and context.is_admin:
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service = db.service_get_by_args(elevated, host, 'nova-compute')
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if not self.service_is_up(service):
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raise exception.WillNotSchedule(host=host)
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return host
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results = db.service_get_all_compute_sorted(elevated)
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in_isolation = instance_opts['image_ref'] in FLAGS.isolated_images
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check_cores = not in_isolation or not FLAGS.skip_isolated_core_check
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if zone:
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results = [(service, cores) for (service, cores) in results
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if service['availability_zone'] == zone]
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for result in results:
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(service, instance_cores) = result
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if in_isolation and service['host'] not in FLAGS.isolated_hosts:
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# isloated images run on isolated hosts
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continue
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if service['host'] in FLAGS.isolated_hosts and not in_isolation:
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# images that aren't isolated only run on general hosts
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continue
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if check_cores and \
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instance_cores + instance_opts['vcpus'] > FLAGS.max_cores:
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msg = _("Not enough allocatable CPU cores remaining")
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raise exception.NoValidHost(reason=msg)
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if self.service_is_up(service):
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return service['host']
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msg = _("Is the appropriate service running?")
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raise exception.NoValidHost(reason=msg)
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def schedule_run_instance(self, context, request_spec, *_args, **_kwargs):
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num_instances = request_spec.get('num_instances', 1)
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instances = []
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for num in xrange(num_instances):
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host = self._schedule_instance(context,
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request_spec['instance_properties'], *_args, **_kwargs)
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instance_ref = self.create_instance_db_entry(context,
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request_spec)
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driver.cast_to_compute_host(context, host, 'run_instance',
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instance_uuid=instance_ref['uuid'], **_kwargs)
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instances.append(driver.encode_instance(instance_ref))
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# So if we loop around, create_instance_db_entry will actually
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# create a new entry, instead of assume it's been created
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# already
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del request_spec['instance_properties']['uuid']
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return instances
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def schedule_start_instance(self, context, instance_id, *_args, **_kwargs):
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instance_ref = db.instance_get(context, instance_id)
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host = self._schedule_instance(context, instance_ref,
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*_args, **_kwargs)
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driver.cast_to_compute_host(context, host, 'start_instance',
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instance_id=instance_id, **_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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elevated = context.elevated()
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volume_ref = db.volume_get(context, volume_id)
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availability_zone = volume_ref.get('availability_zone')
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zone, host = None, None
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if availability_zone:
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zone, _x, host = availability_zone.partition(':')
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if host and context.is_admin:
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service = db.service_get_by_args(elevated, host, 'nova-volume')
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if not self.service_is_up(service):
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raise exception.WillNotSchedule(host=host)
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driver.cast_to_volume_host(context, host, 'create_volume',
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volume_id=volume_id, **_kwargs)
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return None
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results = db.service_get_all_volume_sorted(elevated)
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if zone:
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results = [(service, gigs) for (service, gigs) in results
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if service['availability_zone'] == zone]
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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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msg = _("Not enough allocatable volume gigabytes remaining")
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raise exception.NoValidHost(reason=msg)
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if self.service_is_up(service):
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driver.cast_to_volume_host(context, service['host'],
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'create_volume', volume_id=volume_id, **_kwargs)
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return None
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msg = _("Is the appropriate service running?")
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raise exception.NoValidHost(reason=msg)
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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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elevated = context.elevated()
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results = db.service_get_all_network_sorted(elevated)
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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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msg = _("Not enough allocatable networks remaining")
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raise exception.NoValidHost(reason=msg)
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if self.service_is_up(service):
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driver.cast_to_network_host(context, service['host'],
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'set_network_host', **_kwargs)
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return None
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msg = _("Is the appropriate service running?")
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raise exception.NoValidHost(reason=msg)
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