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OpenStack Study: l3_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 abc import random import six from sqlalchemy.orm import exc from sqlalchemy.sql import exists from neutron.common import constants from neutron.db import agents_db from neutron.db import l3_agentschedulers_db from neutron.db import l3_db from neutron.openstack.common import log as logging LOG = logging.getLogger(__name__) @six.add_metaclass(abc.ABCMeta)
**** CubicPower OpenStack Study **** class L3Scheduler(object): @abc.abstractmethod
**** CubicPower OpenStack Study **** def schedule(self, plugin, context, router_id): """Schedule the router to an active L3 agent. Schedule the router only if it is not already scheduled. """ pass
**** CubicPower OpenStack Study **** def auto_schedule_routers(self, plugin, context, host, router_ids): """Schedule non-hosted routers to L3 Agent running on host. If router_ids is given, each router in router_ids is scheduled if it is not scheduled yet. Otherwise all unscheduled routers are scheduled. Don't schedule the routers which are hosted already by active l3 agents. """ with context.session.begin(subtransactions=True): # query if we have valid l3 agent on the host query = context.session.query(agents_db.Agent) query = query.filter(agents_db.Agent.agent_type == constants.AGENT_TYPE_L3, agents_db.Agent.host == host, agents_db.Agent.admin_state_up == True) try: l3_agent = query.one() except (exc.MultipleResultsFound, exc.NoResultFound): LOG.debug(_('No enabled L3 agent on host %s'), host) return False if agents_db.AgentDbMixin.is_agent_down( l3_agent.heartbeat_timestamp): LOG.warn(_('L3 agent %s is not active'), l3_agent.id) # check if each of the specified routers is hosted if router_ids: unscheduled_router_ids = [] for router_id in router_ids: l3_agents = plugin.get_l3_agents_hosting_routers( context, [router_id], admin_state_up=True) if l3_agents: LOG.debug(_('Router %(router_id)s has already been' ' hosted by L3 agent %(agent_id)s'), {'router_id': router_id, 'agent_id': l3_agents[0]['id']}) else: unscheduled_router_ids.append(router_id) if not unscheduled_router_ids: # all (specified) routers are already scheduled return False else: # get all routers that are not hosted #TODO(gongysh) consider the disabled agent's router stmt = ~exists().where( l3_db.Router.id == l3_agentschedulers_db.RouterL3AgentBinding.router_id) unscheduled_router_ids = [router_id_[0] for router_id_ in context.session.query( l3_db.Router.id).filter(stmt)] if not unscheduled_router_ids: LOG.debug(_('No non-hosted routers')) return False # check if the configuration of l3 agent is compatible # with the router routers = plugin.get_routers( context, filters={'id': unscheduled_router_ids}) to_removed_ids = [] for router in routers: candidates = plugin.get_l3_agent_candidates(router, [l3_agent]) if not candidates: to_removed_ids.append(router['id']) router_ids = set([r['id'] for r in routers]) - set(to_removed_ids) if not router_ids: LOG.warn(_('No routers compatible with L3 agent configuration' ' on host %s'), host) return False for router_id in router_ids: self.bind_router(context, router_id, l3_agent) return True
**** CubicPower OpenStack Study **** def get_candidates(self, plugin, context, sync_router): """Return L3 agents where a router could be scheduled.""" with context.session.begin(subtransactions=True): # allow one router is hosted by just # one enabled l3 agent hosting since active is just a # timing problem. Non-active l3 agent can return to # active any time l3_agents = plugin.get_l3_agents_hosting_routers( context, [sync_router['id']], admin_state_up=True) if l3_agents: LOG.debug(_('Router %(router_id)s has already been hosted' ' by L3 agent %(agent_id)s'), {'router_id': sync_router['id'], 'agent_id': l3_agents[0]['id']}) return active_l3_agents = plugin.get_l3_agents(context, active=True) if not active_l3_agents: LOG.warn(_('No active L3 agents')) return candidates = plugin.get_l3_agent_candidates(sync_router, active_l3_agents) if not candidates: LOG.warn(_('No L3 agents can host the router %s'), sync_router['id']) return return candidates
**** CubicPower OpenStack Study **** def bind_router(self, context, router_id, chosen_agent): """Bind the router to the l3 agent which has been chosen.""" with context.session.begin(subtransactions=True): binding = l3_agentschedulers_db.RouterL3AgentBinding() binding.l3_agent = chosen_agent binding.router_id = router_id context.session.add(binding) LOG.debug(_('Router %(router_id)s is scheduled to ' 'L3 agent %(agent_id)s'), {'router_id': router_id, 'agent_id': chosen_agent.id})
**** CubicPower OpenStack Study **** class ChanceScheduler(L3Scheduler): """Randomly allocate an L3 agent for a router."""
**** CubicPower OpenStack Study **** def schedule(self, plugin, context, router_id): with context.session.begin(subtransactions=True): sync_router = plugin.get_router(context, router_id) candidates = self.get_candidates(plugin, context, sync_router) if not candidates: return chosen_agent = random.choice(candidates) self.bind_router(context, router_id, chosen_agent) return chosen_agent
**** CubicPower OpenStack Study **** class LeastRoutersScheduler(L3Scheduler): """Allocate to an L3 agent with the least number of routers bound."""
**** CubicPower OpenStack Study **** def schedule(self, plugin, context, router_id): with context.session.begin(subtransactions=True): sync_router = plugin.get_router(context, router_id) candidates = self.get_candidates(plugin, context, sync_router) if not candidates: return candidate_ids = [candidate['id'] for candidate in candidates] chosen_agent = plugin.get_l3_agent_with_min_routers( context, candidate_ids) self.bind_router(context, router_id, chosen_agent) return chosen_agent
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