Merge "Event driven periodic resync task for DHCP agents"
This commit is contained in:
Zuul
Gerrit Code Review
commit
aefd805cca
@ -15,6 +15,7 @@
|
||||
|
||||
import collections
|
||||
import os
|
||||
import threading
|
||||
|
||||
import eventlet
|
||||
from neutron_lib.agent import constants as agent_consts
|
||||
@ -86,6 +87,15 @@ class DhcpAgent(manager.Manager):
|
||||
self.needs_resync_reasons = collections.defaultdict(list)
|
||||
self.dhcp_ready_ports = set()
|
||||
self.conf = conf or cfg.CONF
|
||||
# If 'resync_throttle' is configured more than 'resync_interval' by
|
||||
# mistake, raise exception and log with message.
|
||||
if self.conf.resync_throttle > self.conf.resync_interval:
|
||||
msg = _("DHCP agent must have resync_throttle <= resync_interval")
|
||||
LOG.exception(msg)
|
||||
raise exceptions.InvalidConfigurationOption(
|
||||
opt_name='resync_throttle',
|
||||
opt_value=self.conf.resync_throttle)
|
||||
self._periodic_resync_event = threading.Event()
|
||||
self.cache = NetworkCache()
|
||||
self.dhcp_driver_cls = importutils.import_class(self.conf.dhcp_driver)
|
||||
self.plugin_rpc = DhcpPluginApi(topics.PLUGIN, self.conf.host)
|
||||
@ -174,6 +184,12 @@ class DhcpAgent(manager.Manager):
|
||||
specified, resync all networks.
|
||||
"""
|
||||
self.needs_resync_reasons[network_id].append(reason)
|
||||
self._periodic_resync_event.set()
|
||||
# Yield to allow other threads that may be ready to run.
|
||||
# This helps prevent one thread from acquiring the same lock over and
|
||||
# over again, in which case no other threads waiting on the
|
||||
# "dhcp-agent" lock would make any progress.
|
||||
eventlet.greenthread.sleep(0)
|
||||
|
||||
@_sync_lock
|
||||
def sync_state(self, networks=None):
|
||||
@ -243,9 +259,20 @@ class DhcpAgent(manager.Manager):
|
||||
|
||||
@utils.exception_logger()
|
||||
def _periodic_resync_helper(self):
|
||||
"""Resync the dhcp state at the configured interval."""
|
||||
"""Resync the dhcp state at the configured interval and throttle."""
|
||||
while True:
|
||||
eventlet.sleep(self.conf.resync_interval)
|
||||
# threading.Event.wait blocks until the internal flag is true. It
|
||||
# returns the internal flag on exit, so it will always return True
|
||||
# except if a timeout is given and the operation times out.
|
||||
if self._periodic_resync_event.wait(self.conf.resync_interval):
|
||||
LOG.debug("Resync event has been scheduled")
|
||||
clear_periodic_resync_event = self._periodic_resync_event.clear
|
||||
# configure throttler for clear_periodic_resync_event to
|
||||
# introduce delays between resync state events.
|
||||
throttled_clear_periodic_resync_event = utils.throttler(
|
||||
self.conf.resync_throttle)(clear_periodic_resync_event)
|
||||
throttled_clear_periodic_resync_event()
|
||||
|
||||
if self.needs_resync_reasons:
|
||||
# be careful to avoid a race with additions to list
|
||||
# from other threads
|
||||
|
||||
@ -24,7 +24,17 @@ DHCP_AGENT_OPTS = [
|
||||
cfg.IntOpt('resync_interval', default=5,
|
||||
help=_("The DHCP agent will resync its state with Neutron to "
|
||||
"recover from any transient notification or RPC errors. "
|
||||
"The interval is number of seconds between attempts.")),
|
||||
"The interval is maximum number of seconds between "
|
||||
"attempts. The resync can be done more often based on "
|
||||
"the events triggered.")),
|
||||
cfg.IntOpt('resync_throttle', default=1,
|
||||
help=_("Throttle the number of resync state events between the "
|
||||
"local DHCP state and Neutron to only once per "
|
||||
"'resync_throttle' seconds. The value of throttle "
|
||||
"introduces a minimum interval between resync state "
|
||||
"events. Otherwise the resync may end up in a "
|
||||
"busy-loop. The value must be less than "
|
||||
"resync_interval.")),
|
||||
cfg.StrOpt('dhcp_driver',
|
||||
default='neutron.agent.linux.dhcp.Dnsmasq',
|
||||
help=_("The driver used to manage the DHCP server.")),
|
||||
|
||||
@ -242,6 +242,26 @@ class TestDhcpAgent(base.BaseTestCase):
|
||||
"IPWrapper")
|
||||
self.mock_ip_wrapper = self.mock_ip_wrapper_p.start()
|
||||
|
||||
def test_init_resync_throttle_conf(self):
|
||||
try:
|
||||
dhcp_agent.DhcpAgent(HOSTNAME)
|
||||
except exceptions.InvalidConfigurationOption:
|
||||
self.fail("DHCP agent initialization unexpectedly raised an "
|
||||
"InvalidConfigurationOption exception. No exception is "
|
||||
"expected with the default configurations.")
|
||||
|
||||
# default resync_interval = 5; default resync_throttle = 1
|
||||
cfg.CONF.set_override('resync_throttle', 10)
|
||||
# resync_throttle must be <= resync_interval, otherwise an
|
||||
# InvalidConfigurationOption exception would be raised with log
|
||||
# message.
|
||||
with mock.patch.object(dhcp_agent.LOG, 'exception') as log:
|
||||
with testtools.ExpectedException(
|
||||
exceptions.InvalidConfigurationOption):
|
||||
dhcp_agent.DhcpAgent(HOSTNAME)
|
||||
log.assert_any_call("DHCP agent must have resync_throttle <= "
|
||||
"resync_interval")
|
||||
|
||||
def test_init_host(self):
|
||||
dhcp = dhcp_agent.DhcpAgent(HOSTNAME)
|
||||
with mock.patch.object(dhcp, 'sync_state') as sync_state:
|
||||
@ -489,18 +509,30 @@ class TestDhcpAgent(base.BaseTestCase):
|
||||
['Agent has just been revived'])
|
||||
|
||||
def test_periodic_resync_helper(self):
|
||||
with mock.patch.object(dhcp_agent.eventlet, 'sleep') as sleep:
|
||||
dhcp = dhcp_agent.DhcpAgent(HOSTNAME)
|
||||
resync_reasons = collections.OrderedDict(
|
||||
(('a', 'reason1'), ('b', 'reason2')))
|
||||
dhcp.needs_resync_reasons = resync_reasons
|
||||
with mock.patch.object(dhcp, 'sync_state') as sync_state:
|
||||
sync_state.side_effect = RuntimeError
|
||||
with testtools.ExpectedException(RuntimeError):
|
||||
dhcp._periodic_resync_helper()
|
||||
sync_state.assert_called_once_with(resync_reasons.keys())
|
||||
self.assertEqual(0, len(dhcp.needs_resync_reasons))
|
||||
|
||||
def test_periodic_resync_helper_with_event(self):
|
||||
with mock.patch.object(dhcp_agent.LOG, 'debug') as log:
|
||||
dhcp = dhcp_agent.DhcpAgent(HOSTNAME)
|
||||
resync_reasons = collections.OrderedDict(
|
||||
(('a', 'reason1'), ('b', 'reason2')))
|
||||
dhcp.needs_resync_reasons = resync_reasons
|
||||
dhcp.schedule_resync('reason1', 'a')
|
||||
dhcp.schedule_resync('reason1', 'b')
|
||||
reasons = dhcp.needs_resync_reasons.keys()
|
||||
with mock.patch.object(dhcp, 'sync_state') as sync_state:
|
||||
sync_state.side_effect = RuntimeError
|
||||
with testtools.ExpectedException(RuntimeError):
|
||||
dhcp._periodic_resync_helper()
|
||||
sync_state.assert_called_once_with(resync_reasons.keys())
|
||||
sleep.assert_called_once_with(dhcp.conf.resync_interval)
|
||||
self.assertEqual(0, len(dhcp.needs_resync_reasons))
|
||||
log.assert_any_call("Resync event has been scheduled")
|
||||
sync_state.assert_called_once_with(reasons)
|
||||
self.assertEqual(0, len(dhcp.needs_resync_reasons))
|
||||
|
||||
def test_populate_cache_on_start_without_active_networks_support(self):
|
||||
# emul dhcp driver that doesn't support retrieving of active networks
|
||||
|
||||
@ -0,0 +1,17 @@
|
||||
---
|
||||
features:
|
||||
-
|
||||
A new config option ``resync_throttle`` has been added for Neutron DHCP
|
||||
agent.
|
||||
This new option allows to throttle the number of resync state events
|
||||
between the local DHCP state and Neutron to only once per
|
||||
``resync_throttle`` seconds.
|
||||
Default value for this new option is set to 1 and it should be configured
|
||||
per a user's specific scenario, i.e. how responsive the user would like
|
||||
his/her system to be for those DHCP resync state events.
|
||||
The option is introduced together with the event driven periodic task for
|
||||
DHCP agents. This enhances the agent with a faster reaction on the resync
|
||||
request but ensuring a minimum interval taken between them to avoid too
|
||||
frequent resyncing.
|
||||
For more information see bug
|
||||
`1780370 <https://bugs.launchpad.net/neutron/+bug/1780370>`_.
|
||||
Loading…
x
Reference in New Issue
Block a user