vmware-nsx/quantum/scheduler/dhcp_agent_scheduler.py
Maru Newby a13295b9a8 Enable automatic validation of many HACKING rules.
* Add hacking to the tox build - a set of flake8 plugins that
   perform automatic validation of many HACKING.rst rules.
 * This patch configures hacking in the tox build and performs
   the mechanical cleanup required to allow the checks to pass.
 * See https://pypi.python.org/pypi/hacking

Change-Id: Ie9b3eb5627a9b6dd181f79225abae422e6cf3777
2013-04-11 19:48:28 +00:00

111 lines
4.6 KiB
Python

# 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 sqlalchemy.orm import exc
from sqlalchemy.sql import exists
from quantum.common import constants
from quantum.db import agents_db
from quantum.db import agentschedulers_db
from quantum.db import models_v2
from quantum.openstack.common import log as logging
LOG = logging.getLogger(__name__)
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.
"""
def schedule(self, plugin, context, network):
"""Schedule the network to an active DHCP agent if there
is no active DHCP agent hosting it.
"""
#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 dhcp_agents:
LOG.debug(_('Network %s is hosted already'),
network['id'])
return
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 enabled DHCP agents'))
return
active_dhcp_agents = [enabled_dhcp_agent for enabled_dhcp_agent in
enabled_dhcp_agents if not
agents_db.AgentDbMixin.is_agent_down(
enabled_dhcp_agent['heartbeat_timestamp'])]
if not active_dhcp_agents:
LOG.warn(_('No active DHCP agents'))
return
chosen_agent = random.choice(active_dhcp_agents)
binding = agentschedulers_db.NetworkDhcpAgentBinding()
binding.dhcp_agent = chosen_agent
binding.network_id = network['id']
context.session.add(binding)
LOG.debug(_('Network %(network_id)s is scheduled to be hosted by '
'DHCP agent %(agent_id)s'),
{'network_id': network['id'],
'agent_id': chosen_agent['id']})
return chosen_agent
def auto_schedule_networks(self, plugin, context, host):
"""Schedule non-hosted networks to the DHCP agent on
the specified host.
"""
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)
try:
dhcp_agent = query.one()
except (exc.MultipleResultsFound, exc.NoResultFound):
LOG.warn(_('No enabled DHCP agent on host %s'),
host)
return False
if agents_db.AgentDbMixin.is_agent_down(
dhcp_agent.heartbeat_timestamp):
LOG.warn(_('DHCP agent %s is not active'), dhcp_agent.id)
#TODO(gongysh) consider the disabled agent's network
net_stmt = ~exists().where(
models_v2.Network.id ==
agentschedulers_db.NetworkDhcpAgentBinding.network_id)
net_ids = context.session.query(
models_v2.Network.id).filter(net_stmt).all()
if not net_ids:
LOG.debug(_('No non-hosted networks'))
return False
for net_id in net_ids:
binding = agentschedulers_db.NetworkDhcpAgentBinding()
binding.dhcp_agent = dhcp_agent
binding.network_id = net_id[0]
context.session.add(binding)
return True