# 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 datetime import random import time from oslo.config import cfg from oslo.db import exception as db_exc from oslo import messaging from oslo.utils import timeutils import sqlalchemy as sa from sqlalchemy import func from sqlalchemy import orm from sqlalchemy.orm import exc from sqlalchemy.orm import joinedload from sqlalchemy import sql from neutron.common import constants from neutron.common import utils as n_utils from neutron import context as n_ctx from neutron.db import agents_db from neutron.db import agentschedulers_db from neutron.db import l3_attrs_db from neutron.db import model_base from neutron.extensions import l3agentscheduler from neutron.i18n import _LE, _LI, _LW from neutron import manager from neutron.openstack.common import log as logging from neutron.openstack.common import loopingcall LOG = logging.getLogger(__name__) L3_AGENTS_SCHEDULER_OPTS = [ cfg.StrOpt('router_scheduler_driver', default='neutron.scheduler.l3_agent_scheduler.ChanceScheduler', help=_('Driver to use for scheduling ' 'router to a default L3 agent')), cfg.BoolOpt('router_auto_schedule', default=True, help=_('Allow auto scheduling of routers to L3 agent.')), cfg.BoolOpt('allow_automatic_l3agent_failover', default=False, help=_('Automatically reschedule routers from offline L3 ' 'agents to online L3 agents.')), ] cfg.CONF.register_opts(L3_AGENTS_SCHEDULER_OPTS) class RouterL3AgentBinding(model_base.BASEV2): """Represents binding between neutron routers and L3 agents.""" router_id = sa.Column(sa.String(36), sa.ForeignKey("routers.id", ondelete='CASCADE'), primary_key=True) l3_agent = orm.relation(agents_db.Agent) l3_agent_id = sa.Column(sa.String(36), sa.ForeignKey("agents.id", ondelete='CASCADE'), primary_key=True) class L3AgentSchedulerDbMixin(l3agentscheduler.L3AgentSchedulerPluginBase, agentschedulers_db.AgentSchedulerDbMixin): """Mixin class to add l3 agent scheduler extension to plugins using the l3 agent for routing. """ router_scheduler = None def start_periodic_agent_status_check(self): if not cfg.CONF.allow_automatic_l3agent_failover: LOG.info(_LI("Skipping period L3 agent status check because " "automatic router rescheduling is disabled.")) return self.periodic_agent_loop = loopingcall.FixedIntervalLoopingCall( self.reschedule_routers_from_down_agents) interval = max(cfg.CONF.agent_down_time / 2, 1) # add random initial delay to allow agents to check in after the # neutron server first starts. random to offset multiple servers self.periodic_agent_loop.start(interval=interval, initial_delay=random.randint(interval, interval * 2)) def reschedule_routers_from_down_agents(self): """Reschedule routers from down l3 agents if admin state is up.""" # give agents extra time to handle transient failures agent_dead_limit = cfg.CONF.agent_down_time * 2 # check for an abrupt clock change since last check. if a change is # detected, sleep for a while to let the agents check in. tdelta = timeutils.utcnow() - getattr(self, '_clock_jump_canary', timeutils.utcnow()) if timeutils.total_seconds(tdelta) > cfg.CONF.agent_down_time: LOG.warn(_LW("Time since last L3 agent reschedule check has " "exceeded the interval between checks. Waiting " "before check to allow agents to send a heartbeat " "in case there was a clock adjustment.")) time.sleep(agent_dead_limit) self._clock_jump_canary = timeutils.utcnow() context = n_ctx.get_admin_context() cutoff = timeutils.utcnow() - datetime.timedelta( seconds=agent_dead_limit) down_bindings = ( context.session.query(RouterL3AgentBinding). join(agents_db.Agent). filter(agents_db.Agent.heartbeat_timestamp < cutoff, agents_db.Agent.admin_state_up). outerjoin(l3_attrs_db.RouterExtraAttributes, l3_attrs_db.RouterExtraAttributes.router_id == RouterL3AgentBinding.router_id). filter(sa.or_(l3_attrs_db.RouterExtraAttributes.ha == sql.false(), l3_attrs_db.RouterExtraAttributes.ha == sql.null()))) try: for binding in down_bindings: LOG.warn(_LW( "Rescheduling router %(router)s from agent %(agent)s " "because the agent did not report to the server in " "the last %(dead_time)s seconds."), {'router': binding.router_id, 'agent': binding.l3_agent_id, 'dead_time': agent_dead_limit}) try: self.reschedule_router(context, binding.router_id) except (l3agentscheduler.RouterReschedulingFailed, messaging.RemoteError): # Catch individual router rescheduling errors here # so one broken one doesn't stop the iteration. LOG.exception(_LE("Failed to reschedule router %s"), binding.router_id) except db_exc.DBError: # Catch DB errors here so a transient DB connectivity issue # doesn't stop the loopingcall. LOG.exception(_LE("Exception encountered during router " "rescheduling.")) def validate_agent_router_combination(self, context, agent, router): """Validate if the router can be correctly assigned to the agent. :raises: RouterL3AgentMismatch if attempting to assign DVR router to legacy agent, or centralized router to compute's L3 agents. :raises: InvalidL3Agent if attempting to assign router to an unsuitable agent (disabled, type != L3, incompatible configuration) """ is_distributed = router.get('distributed') agent_conf = self.get_configuration_dict(agent) agent_mode = agent_conf.get('agent_mode', 'legacy') is_agent_router_types_incompatible = ( agent_mode == 'dvr' and not is_distributed or agent_mode == 'legacy' and is_distributed ) if is_agent_router_types_incompatible: router_type = ('distributed' if is_distributed else 'centralized') raise l3agentscheduler.RouterL3AgentMismatch( router_type=router_type, router_id=router['id'], agent_mode=agent_mode, agent_id=agent['id']) is_wrong_type_or_unsuitable_agent = ( agent['agent_type'] != constants.AGENT_TYPE_L3 or not agent['admin_state_up'] or not self.get_l3_agent_candidates(context, router, [agent]) ) if is_wrong_type_or_unsuitable_agent: raise l3agentscheduler.InvalidL3Agent(id=agent['id']) def check_agent_router_scheduling_needed(self, context, agent, router): """Check if the router scheduling is needed. :raises: RouterHostedByL3Agent if router is already assigned to a different agent. :returns: True if scheduling is needed, otherwise False """ router_id = router['id'] agent_id = agent['id'] query = context.session.query(RouterL3AgentBinding) bindings = query.filter_by(router_id=router_id).all() if not bindings: return True for binding in bindings: if binding.l3_agent_id == agent_id: # router already bound to the agent we need return False if router.get('distributed'): return False # non-dvr case: centralized router is already bound to some agent raise l3agentscheduler.RouterHostedByL3Agent( router_id=router_id, agent_id=bindings[0].l3_agent_id) def create_router_to_agent_binding(self, context, agent, router): """Create router to agent binding.""" router_id = router['id'] agent_id = agent['id'] if self.router_scheduler: try: self.router_scheduler.bind_router(context, router_id, agent) except db_exc.DBError: raise l3agentscheduler.RouterSchedulingFailed( router_id=router_id, agent_id=agent_id) def add_router_to_l3_agent(self, context, agent_id, router_id): """Add a l3 agent to host a router.""" with context.session.begin(subtransactions=True): router = self.get_router(context, router_id) agent = self._get_agent(context, agent_id) self.validate_agent_router_combination(context, agent, router) if self.check_agent_router_scheduling_needed( context, agent, router): self.create_router_to_agent_binding(context, agent, router) else: return l3_notifier = self.agent_notifiers.get(constants.AGENT_TYPE_L3) if l3_notifier: l3_notifier.router_added_to_agent( context, [router_id], agent.host) def remove_router_from_l3_agent(self, context, agent_id, router_id): """Remove the router from l3 agent. After removal, the router will be non-hosted until there is update which leads to re-schedule or be added to another agent manually. """ agent = self._get_agent(context, agent_id) self._unbind_router(context, router_id, agent_id) l3_notifier = self.agent_notifiers.get(constants.AGENT_TYPE_L3) if l3_notifier: l3_notifier.router_removed_from_agent( context, router_id, agent.host) def _unbind_router(self, context, router_id, agent_id): with context.session.begin(subtransactions=True): query = context.session.query(RouterL3AgentBinding) query = query.filter( RouterL3AgentBinding.router_id == router_id, RouterL3AgentBinding.l3_agent_id == agent_id) try: binding = query.one() except exc.NoResultFound: raise l3agentscheduler.RouterNotHostedByL3Agent( router_id=router_id, agent_id=agent_id) context.session.delete(binding) def reschedule_router(self, context, router_id, candidates=None): """Reschedule router to a new l3 agent Remove the router from the agent(s) currently hosting it and schedule it again """ cur_agents = self.list_l3_agents_hosting_router( context, router_id)['agents'] with context.session.begin(subtransactions=True): for agent in cur_agents: self._unbind_router(context, router_id, agent['id']) new_agent = self.schedule_router(context, router_id, candidates=candidates) if not new_agent: raise l3agentscheduler.RouterReschedulingFailed( router_id=router_id) l3_notifier = self.agent_notifiers.get(constants.AGENT_TYPE_L3) if l3_notifier: for agent in cur_agents: l3_notifier.router_removed_from_agent( context, router_id, agent['host']) l3_notifier.router_added_to_agent( context, [router_id], new_agent.host) def list_routers_on_l3_agent(self, context, agent_id): query = context.session.query(RouterL3AgentBinding.router_id) query = query.filter(RouterL3AgentBinding.l3_agent_id == agent_id) router_ids = [item[0] for item in query] if router_ids: return {'routers': self.get_routers(context, filters={'id': router_ids})} else: return {'routers': []} def list_active_sync_routers_on_active_l3_agent( self, context, host, router_ids): agent = self._get_agent_by_type_and_host( context, constants.AGENT_TYPE_L3, host) if not agent.admin_state_up: return [] query = context.session.query(RouterL3AgentBinding.router_id) query = query.filter( RouterL3AgentBinding.l3_agent_id == agent.id) if router_ids: query = query.filter( RouterL3AgentBinding.router_id.in_(router_ids)) router_ids = [item[0] for item in query] if router_ids: if n_utils.is_extension_supported(self, constants.L3_HA_MODE_EXT_ALIAS): return self.get_ha_sync_data_for_host(context, host, router_ids=router_ids, active=True) else: return self.get_sync_data(context, router_ids=router_ids, active=True) else: return [] def get_l3_agents_hosting_routers(self, context, router_ids, admin_state_up=None, active=None): if not router_ids: return [] query = context.session.query(RouterL3AgentBinding) if len(router_ids) > 1: query = query.options(joinedload('l3_agent')).filter( RouterL3AgentBinding.router_id.in_(router_ids)) else: query = query.options(joinedload('l3_agent')).filter( RouterL3AgentBinding.router_id == router_ids[0]) if admin_state_up is not None: query = (query.filter(agents_db.Agent.admin_state_up == admin_state_up)) l3_agents = [binding.l3_agent for binding in query] if active is not None: l3_agents = [l3_agent for l3_agent in l3_agents if not agents_db.AgentDbMixin.is_agent_down( l3_agent['heartbeat_timestamp'])] return l3_agents def _get_l3_bindings_hosting_routers(self, context, router_ids): if not router_ids: return [] query = context.session.query(RouterL3AgentBinding) if len(router_ids) > 1: query = query.options(joinedload('l3_agent')).filter( RouterL3AgentBinding.router_id.in_(router_ids)) else: query = query.options(joinedload('l3_agent')).filter( RouterL3AgentBinding.router_id == router_ids[0]) return query.all() def list_l3_agents_hosting_router(self, context, router_id): with context.session.begin(subtransactions=True): bindings = self._get_l3_bindings_hosting_routers( context, [router_id]) results = [] for binding in bindings: l3_agent_dict = self._make_agent_dict(binding.l3_agent) results.append(l3_agent_dict) if results: return {'agents': results} else: return {'agents': []} def get_l3_agents(self, context, active=None, filters=None): query = context.session.query(agents_db.Agent) query = query.filter( agents_db.Agent.agent_type == constants.AGENT_TYPE_L3) if active is not None: query = (query.filter(agents_db.Agent.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 [l3_agent for l3_agent in query if agentschedulers_db.AgentSchedulerDbMixin.is_eligible_agent( active, l3_agent)] def check_ports_exist_on_l3agent(self, context, l3_agent, router_id): """ This function checks for existence of dvr serviceable ports on the host, running the input l3agent. """ subnet_ids = self.get_subnet_ids_on_router(context, router_id) core_plugin = manager.NeutronManager.get_plugin() filter = {'fixed_ips': {'subnet_id': subnet_ids}} ports = core_plugin.get_ports(context, filters=filter) for port in ports: if (n_utils.is_dvr_serviced(port['device_owner']) and l3_agent['host'] == port['binding:host_id']): return True return False def get_snat_candidates(self, sync_router, l3_agents): """Get the valid snat enabled l3 agents for the distributed router.""" candidates = [] is_router_distributed = sync_router.get('distributed', False) if not is_router_distributed: return candidates for l3_agent in l3_agents: if not l3_agent.admin_state_up: continue agent_conf = self.get_configuration_dict(l3_agent) agent_mode = agent_conf.get('agent_mode', 'legacy') if agent_mode != 'dvr_snat': continue router_id = agent_conf.get('router_id', None) use_namespaces = agent_conf.get('use_namespaces', True) if not use_namespaces and router_id != sync_router['id']: continue handle_internal_only_routers = agent_conf.get( 'handle_internal_only_routers', True) gateway_external_network_id = agent_conf.get( 'gateway_external_network_id', None) ex_net_id = (sync_router['external_gateway_info'] or {}).get( 'network_id') if ((not ex_net_id and not handle_internal_only_routers) or (ex_net_id and gateway_external_network_id and ex_net_id != gateway_external_network_id)): continue candidates.append(l3_agent) return candidates def get_l3_agent_candidates(self, context, sync_router, l3_agents): """Get the valid l3 agents for the router from a list of l3_agents.""" candidates = [] for l3_agent in l3_agents: if not l3_agent.admin_state_up: continue agent_conf = self.get_configuration_dict(l3_agent) router_id = agent_conf.get('router_id', None) use_namespaces = agent_conf.get('use_namespaces', True) handle_internal_only_routers = agent_conf.get( 'handle_internal_only_routers', True) gateway_external_network_id = agent_conf.get( 'gateway_external_network_id', None) agent_mode = agent_conf.get('agent_mode', 'legacy') if not use_namespaces and router_id != sync_router['id']: continue ex_net_id = (sync_router['external_gateway_info'] or {}).get( 'network_id') if ((not ex_net_id and not handle_internal_only_routers) or (ex_net_id and gateway_external_network_id and ex_net_id != gateway_external_network_id)): continue is_router_distributed = sync_router.get('distributed', False) if agent_mode in ('legacy', 'dvr_snat') and ( not is_router_distributed): candidates.append(l3_agent) elif is_router_distributed and agent_mode.startswith('dvr') and ( self.check_ports_exist_on_l3agent( context, l3_agent, sync_router['id'])): candidates.append(l3_agent) return candidates def auto_schedule_routers(self, context, host, router_ids): if self.router_scheduler: return self.router_scheduler.auto_schedule_routers( self, context, host, router_ids) def schedule_router(self, context, router, candidates=None): if self.router_scheduler: return self.router_scheduler.schedule( self, context, router, candidates=candidates) def schedule_routers(self, context, routers): """Schedule the routers to l3 agents.""" for router in routers: self.schedule_router(context, router, candidates=None) def get_l3_agent_with_min_routers(self, context, agent_ids): """Return l3 agent with the least number of routers.""" query = context.session.query( agents_db.Agent, func.count( RouterL3AgentBinding.router_id ).label('count')).outerjoin(RouterL3AgentBinding).group_by( RouterL3AgentBinding.l3_agent_id).order_by('count') res = query.filter(agents_db.Agent.id.in_(agent_ids)).first() return res[0]