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OpenStack Study: dhcp_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 from oslo.config import cfg from neutron.common import constants from neutron.db import agents_db from neutron.db import agentschedulers_db from neutron.openstack.common.db import exception as db_exc from neutron.openstack.common import log as logging LOG = logging.getLogger(__name__)
**** CubicPower OpenStack Study **** class ChanceScheduler(object): """Allocate a DHCP agent for a network in a random way. More sophisticated scheduler (similar to filter scheduler in nova?) can be introduced later. """
**** CubicPower OpenStack Study **** def _schedule_bind_network(self, context, agents, network_id): for agent in agents: context.session.begin(subtransactions=True) try: binding = agentschedulers_db.NetworkDhcpAgentBinding() binding.dhcp_agent = agent binding.network_id = network_id context.session.add(binding) # try to actually write the changes and catch integrity # DBDuplicateEntry context.session.commit() except db_exc.DBDuplicateEntry: # it's totally ok, someone just did our job! context.session.rollback() LOG.info(_('Agent %s already present'), agent) LOG.debug(_('Network %(network_id)s is scheduled to be ' 'hosted by DHCP agent %(agent_id)s'), {'network_id': network_id, 'agent_id': agent})
**** CubicPower OpenStack Study **** def schedule(self, plugin, context, network): """Schedule the network to active DHCP agent(s). A list of scheduled agents is returned. """ agents_per_network = cfg.CONF.dhcp_agents_per_network #TODO(gongysh) don't schedule the networks with only # subnets whose enable_dhcp is false with context.session.begin(subtransactions=True): dhcp_agents = plugin.get_dhcp_agents_hosting_networks( context, [network['id']], active=True) if len(dhcp_agents) >= agents_per_network: LOG.debug(_('Network %s is hosted already'), network['id']) return n_agents = agents_per_network - len(dhcp_agents) enabled_dhcp_agents = plugin.get_agents_db( context, filters={ 'agent_type': [constants.AGENT_TYPE_DHCP], 'admin_state_up': [True]}) if not enabled_dhcp_agents: LOG.warn(_('No more DHCP agents')) return active_dhcp_agents = [ agent for agent in set(enabled_dhcp_agents) if not agents_db.AgentDbMixin.is_agent_down( agent['heartbeat_timestamp']) and agent not in dhcp_agents ] if not active_dhcp_agents: LOG.warn(_('No more DHCP agents')) return n_agents = min(len(active_dhcp_agents), n_agents) chosen_agents = random.sample(active_dhcp_agents, n_agents) self._schedule_bind_network(context, chosen_agents, network['id']) return chosen_agents
**** CubicPower OpenStack Study **** def auto_schedule_networks(self, plugin, context, host): """Schedule non-hosted networks to the DHCP agent on the specified host. """ agents_per_network = cfg.CONF.dhcp_agents_per_network with context.session.begin(subtransactions=True): query = context.session.query(agents_db.Agent) query = query.filter(agents_db.Agent.agent_type == constants.AGENT_TYPE_DHCP, agents_db.Agent.host == host, agents_db.Agent.admin_state_up == True) dhcp_agents = query.all() for dhcp_agent in dhcp_agents: if agents_db.AgentDbMixin.is_agent_down( dhcp_agent.heartbeat_timestamp): LOG.warn(_('DHCP agent %s is not active'), dhcp_agent.id) continue fields = ['network_id', 'enable_dhcp'] subnets = plugin.get_subnets(context, fields=fields) net_ids = set(s['network_id'] for s in subnets if s['enable_dhcp']) if not net_ids: LOG.debug(_('No non-hosted networks')) return False for net_id in net_ids: agents = plugin.get_dhcp_agents_hosting_networks( context, [net_id], active=True) if len(agents) >= agents_per_network: continue if any(dhcp_agent.id == agent.id for agent in agents): continue binding = agentschedulers_db.NetworkDhcpAgentBinding() binding.dhcp_agent = dhcp_agent binding.network_id = net_id context.session.add(binding) return True
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