265 lines
11 KiB
Python
265 lines
11 KiB
Python
# Copyright (c) 2011 Openstack, LLC.
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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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The Zone Aware Scheduler is a base class Scheduler for creating instances
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across zones. There are two expansion points to this class for:
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1. Assigning Weights to hosts for requested instances
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2. Filtering Hosts based on required instance capabilities
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"""
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import operator
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import json
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import M2Crypto
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import novaclient
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from nova import crypto
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from nova import db
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from nova import exception
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from nova import flags
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from nova import log as logging
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from nova import rpc
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from nova.scheduler import api
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from nova.scheduler import driver
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FLAGS = flags.FLAGS
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LOG = logging.getLogger('nova.scheduler.zone_aware_scheduler')
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class InvalidBlob(exception.NovaException):
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message = _("Ill-formed or incorrectly routed 'blob' data sent "
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"to instance create request.")
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class ZoneAwareScheduler(driver.Scheduler):
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"""Base class for creating Zone Aware Schedulers."""
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def _call_zone_method(self, context, method, specs):
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"""Call novaclient zone method. Broken out for testing."""
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return api.call_zone_method(context, method, specs=specs)
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def _provision_resource_locally(self, context, item, instance_id, kwargs):
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"""Create the requested resource in this Zone."""
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host = item['hostname']
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kwargs['instance_id'] = instance_id
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rpc.cast(context,
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db.queue_get_for(context, "compute", host),
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{"method": "run_instance",
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"args": kwargs})
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LOG.debug(_("Provisioning locally via compute node %(host)s")
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% locals())
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def _decrypt_blob(self, blob):
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"""Returns the decrypted blob or None if invalid. Broken out
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for testing."""
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decryptor = crypto.decryptor(FLAGS.build_plan_encryption_key)
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try:
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json_entry = decryptor(blob)
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return json.dumps(entry)
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except M2Crypto.EVP.EVPError:
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pass
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return None
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def _ask_child_zone_to_create_instance(self, context, zone_info,
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request_spec, kwargs):
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"""Once we have determined that the request should go to one
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of our children, we need to fabricate a new POST /servers/
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call with the same parameters that were passed into us.
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Note that we have to reverse engineer from our args to get back the
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image, flavor, ipgroup, etc. since the original call could have
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come in from EC2 (which doesn't use these things)."""
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instance_type = request_spec['instance_type']
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instance_properties = request_spec['instance_properties']
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name = instance_properties['display_name']
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image_id = instance_properties['image_id']
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meta = instance_properties['metadata']
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flavor_id = instance_type['flavorid']
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files = kwargs['injected_files']
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ipgroup = None # Not supported in OS API ... yet
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child_zone = zone_info['child_zone']
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child_blob = zone_info['child_blob']
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zone = db.zone_get(context, child_zone)
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url = zone.api_url
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LOG.debug(_("Forwarding instance create call to child zone %(url)s")
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% locals())
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nova = None
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try:
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nova = novaclient.OpenStack(zone.username, zone.password, url)
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nova.authenticate()
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except novaclient.exceptions.BadRequest, e:
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raise exception.NotAuthorized(_("Bad credentials attempting "
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"to talk to zone at %(url)s.") % locals())
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nova.servers.create(name, image_id, flavor_id, ipgroup, meta, files,
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child_blob)
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def _provision_resource_from_blob(self, context, item, instance_id,
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request_spec, kwargs):
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"""Create the requested resource locally or in a child zone
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based on what is stored in the zone blob info.
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Attempt to decrypt the blob to see if this request is:
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1. valid, and
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2. intended for this zone or a child zone.
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Note: If we have "blob" that means the request was passed
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into us from a parent zone. If we have "child_blob" that
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means we gathered the info from one of our children.
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It's possible that, when we decrypt the 'blob' field, it
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contains "child_blob" data. In which case we forward the
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request."""
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host_info = None
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if "blob" in item:
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# Request was passed in from above. Is it for us?
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host_info = self._decrypt_blob(item['blob'])
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elif "child_blob" in item:
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# Our immediate child zone provided this info ...
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host_info = item
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if not host_info:
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raise InvalidBlob()
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# Valid data ... is it for us?
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if 'child_zone' in host_info and 'child_blob' in host_info:
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self._ask_child_zone_to_create_instance(context, host_info,
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request_spec, kwargs)
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else:
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self._provision_resource_locally(context, host_info,
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instance_id, kwargs)
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def _provision_resource(self, context, item, instance_id, request_spec,
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kwargs):
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"""Create the requested resource in this Zone or a child zone."""
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if "hostname" in item:
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self._provision_resource_locally(context, item, instance_id,
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kwargs)
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return
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self._provision_resource_from_blob(context, item, instance_id,
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request_spec, kwargs)
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def schedule_run_instance(self, context, instance_id, request_spec,
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*args, **kwargs):
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"""This method is called from nova.compute.api to provision
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an instance. However we need to look at the parameters being
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passed in to see if this is a request to:
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1. Create a Build Plan and then provision, or
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2. Use the Build Plan information in the request parameters
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to simply create the instance (either in this zone or
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a child zone).
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"""
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# TODO(sandy): We'll have to look for richer specs at some point.
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blob = request_spec.get('blob')
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if blob:
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self._provision_resource(context, request_spec, instance_id,
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request_spec, kwargs)
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return None
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# Create build plan and provision ...
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build_plan = self.select(context, request_spec)
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if not build_plan:
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raise driver.NoValidHost(_('No hosts were available'))
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for item in build_plan:
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self._provision_resource(context, item, instance_id, request_spec,
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kwargs)
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# Returning None short-circuits the routing to Compute (since
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# we've already done it here)
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return None
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def select(self, context, request_spec, *args, **kwargs):
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"""Select returns a list of weights and zone/host information
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corresponding to the best hosts to service the request. Any
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child zone information has been encrypted so as not to reveal
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anything about the children.
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"""
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return self._schedule(context, "compute", request_spec,
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*args, **kwargs)
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# TODO(sandy): We're only focused on compute instances right now,
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# so we don't implement the default "schedule()" method required
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# of Schedulers.
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def schedule(self, context, topic, request_spec, *args, **kwargs):
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"""The schedule() contract requires we return the one
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best-suited host for this request.
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"""
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raise driver.NoValidHost(_('No hosts were available'))
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def _schedule(self, context, topic, request_spec, *args, **kwargs):
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"""Returns a list of hosts that meet the required specs,
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ordered by their fitness.
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"""
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if topic != "compute":
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raise NotImplemented(_("Zone Aware Scheduler only understands "
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"Compute nodes (for now)"))
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#TODO(sandy): how to infer this from OS API params?
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num_instances = 1
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# Filter local hosts based on requirements ...
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host_list = self.filter_hosts(num_instances, request_spec)
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# TODO(sirp): weigh_hosts should also be a function of 'topic' or
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# resources, so that we can apply different objective functions to it
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# then weigh the selected hosts.
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# weighted = [{weight=weight, name=hostname}, ...]
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weighted = self.weigh_hosts(num_instances, request_spec, host_list)
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# Next, tack on the best weights from the child zones ...
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json_spec = json.dumps(request_spec)
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child_results = self._call_zone_method(context, "select",
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specs=json_spec)
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for child_zone, result in child_results:
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for weighting in result:
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# Remember the child_zone so we can get back to
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# it later if needed. This implicitly builds a zone
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# path structure.
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host_dict = {"weight": weighting["weight"],
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"child_zone": child_zone,
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"child_blob": weighting["blob"]}
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weighted.append(host_dict)
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weighted.sort(key=operator.itemgetter('weight'))
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return weighted
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def filter_hosts(self, num, request_spec):
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"""Derived classes must override this method and return
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a list of hosts in [(hostname, capability_dict)] format.
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"""
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# NOTE(sirp): The default logic is the equivalent to AllHostsFilter
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service_states = self.zone_manager.service_states
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return [(host, services)
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for host, services in service_states.iteritems()]
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def weigh_hosts(self, num, request_spec, hosts):
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"""Derived classes may override this to provide more sophisticated
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scheduling objectives
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"""
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# NOTE(sirp): The default logic is the same as the NoopCostFunction
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return [dict(weight=1, hostname=host) for host, caps in hosts]
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