282 lines
13 KiB
Python
282 lines
13 KiB
Python
# Copyright (c) 2013 OpenStack Foundation.
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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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import collections
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from operator import itemgetter
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from neutron_lib.api.definitions import availability_zone as az_def
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from neutron_lib import constants
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from neutron_lib.objects import exceptions
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from oslo_config import cfg
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from oslo_log import log as logging
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from neutron.agent.common import utils as agent_utils
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from neutron.objects import agent as agent_obj
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from neutron.objects import network
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from neutron.scheduler import base_resource_filter
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from neutron.scheduler import base_scheduler
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LOG = logging.getLogger(__name__)
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class AutoScheduler(object):
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def auto_schedule_networks(self, plugin, context, host):
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"""Schedule non-hosted networks to the DHCP agent on the specified
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host.
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"""
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agents_per_network = cfg.CONF.dhcp_agents_per_network
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# a list of (agent, net_ids) tuples
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bindings_to_add = []
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with context.session.begin(subtransactions=True):
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fields = ['network_id', 'enable_dhcp', 'segment_id']
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subnets = plugin.get_subnets(context, fields=fields)
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net_ids = {}
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net_segment_ids = collections.defaultdict(set)
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for s in subnets:
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if s['enable_dhcp']:
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net_segment_ids[s['network_id']].add(s.get('segment_id'))
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for network_id, segment_ids in net_segment_ids.items():
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is_routed_network = any(segment_ids)
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net_ids[network_id] = is_routed_network
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if not net_ids:
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LOG.debug('No non-hosted networks')
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return False
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dhcp_agents = agent_obj.Agent.get_objects(
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context, agent_type=constants.AGENT_TYPE_DHCP,
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host=host, admin_state_up=True)
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segment_host_mapping = network.SegmentHostMapping.get_objects(
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context, host=host)
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segments_on_host = {s.segment_id for s in segment_host_mapping}
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for dhcp_agent in dhcp_agents:
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if agent_utils.is_agent_down(
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dhcp_agent.heartbeat_timestamp):
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LOG.warning('DHCP agent %s is not active', dhcp_agent.id)
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continue
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for net_id, is_routed_network in net_ids.items():
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agents = plugin.get_dhcp_agents_hosting_networks(
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context, [net_id])
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segments_on_network = net_segment_ids[net_id]
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if is_routed_network:
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if len(segments_on_network & segments_on_host) == 0:
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continue
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else:
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if len(agents) >= agents_per_network:
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continue
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if any(dhcp_agent.id == agent.id for agent in agents):
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continue
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net = plugin.get_network(context, net_id)
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az_hints = (net.get(az_def.AZ_HINTS) or
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cfg.CONF.default_availability_zones)
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if (az_hints and
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dhcp_agent['availability_zone'] not in az_hints):
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continue
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bindings_to_add.append((dhcp_agent, net_id))
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# do it outside transaction so particular scheduling results don't
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# make other to fail
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for agent, net_id in bindings_to_add:
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self.resource_filter.bind(context, [agent], net_id)
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return True
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class ChanceScheduler(base_scheduler.BaseChanceScheduler, AutoScheduler):
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def __init__(self):
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super(ChanceScheduler, self).__init__(DhcpFilter())
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class WeightScheduler(base_scheduler.BaseWeightScheduler, AutoScheduler):
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def __init__(self):
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super(WeightScheduler, self).__init__(DhcpFilter())
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class AZAwareWeightScheduler(WeightScheduler):
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def select(self, plugin, context, resource_hostable_agents,
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resource_hosted_agents, num_agents_needed):
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"""AZ aware scheduling
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If the network has multiple AZs, agents are scheduled as
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follows:
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- select AZ with least agents scheduled for the network
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- for AZs with same amount of scheduled agents, the AZ which
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contains least weight agent will be used first
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- choose agent in the AZ with WeightScheduler
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"""
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# The dict to record the agents in each AZ, the record will be sorted
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# according to the weight of agent. So that the agent with less weight
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# will be used first.
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hostable_az_agents = collections.defaultdict(list)
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# The dict to record the number of agents in each AZ. When the number
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# of agents in each AZ is the same and num_agents_needed is less than
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# the number of AZs, we want to select agents with less weight.
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# Use an OrderedDict here, so that the AZ with least weight agent
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# will be recorded first in the case described above. And, as a result,
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# the agent with least weight will be used first.
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num_az_agents = collections.OrderedDict()
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# resource_hostable_agents should be a list with agents in the order of
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# their weight.
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resource_hostable_agents = (
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super(AZAwareWeightScheduler, self).select(
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plugin, context, resource_hostable_agents,
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resource_hosted_agents, len(resource_hostable_agents)))
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for agent in resource_hostable_agents:
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az_agent = agent['availability_zone']
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hostable_az_agents[az_agent].append(agent)
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if az_agent not in num_az_agents:
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num_az_agents[az_agent] = 0
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if num_agents_needed <= 0:
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return []
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for agent in resource_hosted_agents:
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az_agent = agent['availability_zone']
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if az_agent in num_az_agents:
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num_az_agents[az_agent] += 1
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chosen_agents = []
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while num_agents_needed > 0:
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# 'min' will stably output the first min value in the list.
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select_az = min(num_az_agents.items(), key=itemgetter(1))[0]
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# Select the agent in AZ with least weight.
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select_agent = hostable_az_agents[select_az][0]
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chosen_agents.append(select_agent)
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# Update the AZ-agents records.
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del hostable_az_agents[select_az][0]
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if not hostable_az_agents[select_az]:
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del num_az_agents[select_az]
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else:
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num_az_agents[select_az] += 1
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num_agents_needed -= 1
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return chosen_agents
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class DhcpFilter(base_resource_filter.BaseResourceFilter):
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def bind(self, context, agents, network_id):
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"""Bind the network to the agents."""
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# customize the bind logic
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bound_agents = agents[:]
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for agent in agents:
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# saving agent_id to use it after rollback to avoid
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# DetachedInstanceError
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agent_id = agent.id
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try:
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network.NetworkDhcpAgentBinding(context,
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dhcp_agent_id=agent_id, network_id=network_id).create()
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except exceptions.NeutronDbObjectDuplicateEntry:
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# it's totally ok, someone just did our job!
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bound_agents.remove(agent)
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LOG.info('Agent %s already present', agent_id)
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LOG.debug('Network %(network_id)s is scheduled to be '
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'hosted by DHCP agent %(agent_id)s',
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{'network_id': network_id,
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'agent_id': agent_id})
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super(DhcpFilter, self).bind(context, bound_agents, network_id)
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def filter_agents(self, plugin, context, network):
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"""Return the agents that can host the network.
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This function returns a dictionary which has 3 keys.
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n_agents: The number of agents should be scheduled. If n_agents=0,
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all networks are already scheduled or no more agent can host the
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network.
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hostable_agents: A list of agents which can host the network.
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hosted_agents: A list of agents which already hosts the network.
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"""
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agents_dict = self._get_network_hostable_dhcp_agents(
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plugin, context, network)
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if not agents_dict['hostable_agents'] or agents_dict['n_agents'] <= 0:
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return {'n_agents': 0, 'hostable_agents': [],
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'hosted_agents': agents_dict['hosted_agents']}
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return agents_dict
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def _filter_agents_with_network_access(self, plugin, context,
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network, hostable_agents):
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if 'candidate_hosts' in network:
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hostable_dhcp_hosts = network['candidate_hosts']
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else:
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hostable_dhcp_hosts = plugin.filter_hosts_with_network_access(
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context, network['id'],
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[agent['host'] for agent in hostable_agents])
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reachable_agents = [agent for agent in hostable_agents
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if agent['host'] in hostable_dhcp_hosts]
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return reachable_agents
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def _get_dhcp_agents_hosting_network(self, plugin, context, network):
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"""Return dhcp agents hosting the given network or None if a given
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network is already hosted by enough number of agents.
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"""
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agents_per_network = cfg.CONF.dhcp_agents_per_network
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# TODO(gongysh) don't schedule the networks with only
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# subnets whose enable_dhcp is false
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with context.session.begin(subtransactions=True):
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network_hosted_agents = plugin.get_dhcp_agents_hosting_networks(
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context, [network['id']], hosts=network.get('candidate_hosts'))
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if len(network_hosted_agents) >= agents_per_network:
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LOG.debug('Network %s is already hosted by enough agents.',
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network['id'])
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return
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return network_hosted_agents
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def _get_active_agents(self, plugin, context, az_hints):
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"""Return a list of active dhcp agents."""
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with context.session.begin(subtransactions=True):
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filters = {'agent_type': [constants.AGENT_TYPE_DHCP],
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'admin_state_up': [True]}
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if az_hints:
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filters['availability_zone'] = az_hints
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active_dhcp_agents = plugin.get_agent_objects(
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context, filters=filters)
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if not active_dhcp_agents:
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LOG.warning('No more DHCP agents')
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return []
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return active_dhcp_agents
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def _get_network_hostable_dhcp_agents(self, plugin, context, network):
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"""Provide information on hostable DHCP agents for network.
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The returned value includes the number of agents that will actually
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host the given network, a list of DHCP agents that can host the given
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network, and a list of DHCP agents currently hosting the network.
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"""
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hosted_agents = self._get_dhcp_agents_hosting_network(plugin,
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context, network)
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if hosted_agents is None:
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return {'n_agents': 0, 'hostable_agents': [], 'hosted_agents': []}
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n_agents = cfg.CONF.dhcp_agents_per_network - len(hosted_agents)
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az_hints = (network.get(az_def.AZ_HINTS) or
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cfg.CONF.default_availability_zones)
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active_dhcp_agents = self._get_active_agents(plugin, context, az_hints)
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hosted_agent_ids = [agent['id'] for agent in hosted_agents]
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if not active_dhcp_agents:
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return {'n_agents': 0, 'hostable_agents': [],
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'hosted_agents': hosted_agents}
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hostable_dhcp_agents = [
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agent for agent in active_dhcp_agents
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if agent.id not in hosted_agent_ids and plugin.is_eligible_agent(
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context, True, agent)]
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hostable_dhcp_agents = self._filter_agents_with_network_access(
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plugin, context, network, hostable_dhcp_agents)
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if not hostable_dhcp_agents:
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return {'n_agents': 0, 'hostable_agents': [],
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'hosted_agents': hosted_agents}
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n_agents = min(len(hostable_dhcp_agents), n_agents)
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return {'n_agents': n_agents, 'hostable_agents': hostable_dhcp_agents,
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'hosted_agents': hosted_agents}
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