109 lines
4.6 KiB
Python
109 lines
4.6 KiB
Python
# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# 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 random
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from sqlalchemy.orm import exc
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from sqlalchemy.sql import exists
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from quantum.common import constants
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from quantum.db import models_v2
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from quantum.db import agents_db
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from quantum.db import agentschedulers_db
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from quantum.openstack.common import log as logging
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LOG = logging.getLogger(__name__)
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class ChanceScheduler(object):
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"""Allocate a DHCP agent for a network in a random way.
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More sophisticated scheduler (similar to filter scheduler in nova?)
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can be introduced later."""
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def schedule(self, plugin, context, network):
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"""Schedule the network to an active DHCP agent if there
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is no active DHCP agent hosting it.
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"""
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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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dhcp_agents = plugin.get_dhcp_agents_hosting_networks(
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context, [network['id']], active=True)
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if dhcp_agents:
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LOG.debug(_('Network %s is hosted already'),
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network['id'])
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return
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enabled_dhcp_agents = plugin.get_agents_db(
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context, filters={
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'agent_type': [constants.AGENT_TYPE_DHCP],
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'admin_state_up': [True]})
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if not enabled_dhcp_agents:
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LOG.warn(_('No enabled DHCP agents'))
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return
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active_dhcp_agents = [enabled_dhcp_agent for enabled_dhcp_agent in
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enabled_dhcp_agents if not
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agents_db.AgentDbMixin.is_agent_down(
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enabled_dhcp_agent['heartbeat_timestamp'])]
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if not active_dhcp_agents:
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LOG.warn(_('No active DHCP agents'))
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return
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chosen_agent = random.choice(active_dhcp_agents)
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binding = agentschedulers_db.NetworkDhcpAgentBinding()
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binding.dhcp_agent = chosen_agent
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binding.network_id = network['id']
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context.session.add(binding)
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LOG.debug(_('Network %(network_id)s is scheduled to be hosted by '
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'DHCP agent %(agent_id)s'),
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{'network_id': network['id'],
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'agent_id': chosen_agent['id']})
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return chosen_agent
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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
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the specified host."""
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with context.session.begin(subtransactions=True):
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query = context.session.query(agents_db.Agent)
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query = query.filter(agents_db.Agent.agent_type ==
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constants.AGENT_TYPE_DHCP,
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agents_db.Agent.host == host,
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agents_db.Agent.admin_state_up == True)
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try:
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dhcp_agent = query.one()
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except (exc.MultipleResultsFound, exc.NoResultFound):
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LOG.warn(_('No enabled DHCP agent on host %s'),
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host)
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return False
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if agents_db.AgentDbMixin.is_agent_down(
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dhcp_agent.heartbeat_timestamp):
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LOG.warn(_('DHCP agent %s is not active'), dhcp_agent.id)
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#TODO(gongysh) consider the disabled agent's network
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net_stmt = ~exists().where(
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models_v2.Network.id ==
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agentschedulers_db.NetworkDhcpAgentBinding.network_id)
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net_ids = context.session.query(
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models_v2.Network.id).filter(net_stmt).all()
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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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for net_id in net_ids:
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binding = agentschedulers_db.NetworkDhcpAgentBinding()
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binding.dhcp_agent = dhcp_agent
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binding.network_id = net_id[0]
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context.session.add(binding)
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return True
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