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OpenStack Study: agent_scheduler.py**** CubicPower OpenStack Study ****
# vim: tabstop=4 shiftwidth=4 softtabstop=4 # Copyright (c) 2013 OpenStack Foundation. # All Rights Reserved. # # Licensed under the Apache License, Version 2.0 (the "License"); you may # not use this file except in compliance with the License. You may obtain # a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the # License for the specific language governing permissions and limitations # under the License. import random import sqlalchemy as sa from sqlalchemy import orm from sqlalchemy.orm import joinedload from neutron.common import constants from neutron.db import agents_db from neutron.db import agentschedulers_db from neutron.db import model_base from neutron.extensions import lbaas_agentscheduler from neutron.openstack.common import log as logging LOG = logging.getLogger(__name__)
**** CubicPower OpenStack Study **** class PoolLoadbalancerAgentBinding(model_base.BASEV2): """Represents binding between neutron loadbalancer pools and agents.""" pool_id = sa.Column(sa.String(36), sa.ForeignKey("pools.id", ondelete='CASCADE'), primary_key=True) agent = orm.relation(agents_db.Agent) agent_id = sa.Column(sa.String(36), sa.ForeignKey("agents.id", ondelete='CASCADE'))
**** CubicPower OpenStack Study **** class LbaasAgentSchedulerDbMixin(agentschedulers_db.AgentSchedulerDbMixin,
lbaas_agentscheduler
.LbaasAgentSchedulerPluginBase):
**** CubicPower OpenStack Study **** def get_lbaas_agent_hosting_pool(self, context, pool_id, active=None): query = context.session.query(PoolLoadbalancerAgentBinding) query = query.options(joinedload('agent')) binding = query.get(pool_id) if (binding and self.is_eligible_agent( active, binding.agent)): return {'agent': self._make_agent_dict(binding.agent)}
**** CubicPower OpenStack Study **** def get_lbaas_agents(self, context, active=None, filters=None): query = context.session.query(agents_db.Agent) query = query.filter_by(agent_type=constants.AGENT_TYPE_LOADBALANCER) if active is not None: query = query.filter_by(admin_state_up=active) if filters: for key, value in filters.iteritems(): column = getattr(agents_db.Agent, key, None) if column: query = query.filter(column.in_(value)) return [agent for agent in query if self.is_eligible_agent(active, agent)]
**** CubicPower OpenStack Study **** def list_pools_on_lbaas_agent(self, context, id): query = context.session.query(PoolLoadbalancerAgentBinding.pool_id) query = query.filter_by(agent_id=id) pool_ids = [item[0] for item in query] if pool_ids: return {'pools': self.get_pools(context, filters={'id': pool_ids})} else: return {'pools': []}
**** CubicPower OpenStack Study **** def get_lbaas_agent_candidates(self, device_driver, active_agents): candidates = [] for agent in active_agents: agent_conf = self.get_configuration_dict(agent) if device_driver in agent_conf['device_drivers']: candidates.append(agent) return candidates
**** CubicPower OpenStack Study **** class ChanceScheduler(object): """Allocate a loadbalancer agent for a vip in a random way."""
**** CubicPower OpenStack Study **** def schedule(self, plugin, context, pool, device_driver): """Schedule the pool to an active loadbalancer agent if there is no enabled agent hosting it. """ with context.session.begin(subtransactions=True): lbaas_agent = plugin.get_lbaas_agent_hosting_pool( context, pool['id']) if lbaas_agent: LOG.debug(_('Pool %(pool_id)s has already been hosted' ' by lbaas agent %(agent_id)s'), {'pool_id': pool['id'], 'agent_id': lbaas_agent['id']}) return active_agents = plugin.get_lbaas_agents(context, active=True) if not active_agents: LOG.warn(_('No active lbaas agents for pool %s'), pool['id']) return candidates = plugin.get_lbaas_agent_candidates(device_driver, active_agents) if not candidates: LOG.warn(_('No lbaas agent supporting device driver %s'), device_driver) return chosen_agent = random.choice(candidates) binding = PoolLoadbalancerAgentBinding() binding.agent = chosen_agent binding.pool_id = pool['id'] context.session.add(binding) LOG.debug(_('Pool %(pool_id)s is scheduled to ' 'lbaas agent %(agent_id)s'), {'pool_id': pool['id'], 'agent_id': chosen_agent['id']}) return chosen_agent
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