[DVR] Add lock during creation of FIP agent gateway port
In case when new external network is set as gateway network for dvr router, neutron tries to create floating IP agent gateway port. There should be always max 1 such port per network per L3 agent but sometimes when there are 2 requests to set external gateway for 2 different routers executed almost in same time it may happend that there will be 2 such ports created. That will cause error with configuration of one of routers on L3 agent and this will cause e.g. problems with access from VMs to metadata service. Such issues are visible in DVR CI jobs from time to time. Please check related bug for details. This patch adds lock mechanism during creation of such FIP gateway port. Such solution isn't fully solving exising race condition as if 2 requests will be processed by api workers running on 2 different nodes than this race can still happend. But this should mitigate the issue a bit and solve problem in U/S gates at least. For proper fix we should probably add some constraint on database level to prevent creation of 2 such ports for one network and one host but such solution will not be easy to backport to stable branches so I would prefer first to go with this easy workaround. Change-Id: Iabab7e4d36c7d6a876b2b74423efd7106a5f63f6 Related-Bug: #1830763
This commit is contained in:
Slawek Kaplonski
parent
6d9283c1bc
commit
7b81c1bc67
@ -30,6 +30,7 @@ from neutron_lib.exceptions import l3 as l3_exc
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from neutron_lib.plugins import constants as plugin_constants
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from neutron_lib.plugins import directory
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from neutron_lib.plugins import utils as plugin_utils
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from oslo_concurrency import lockutils
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from oslo_config import cfg
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from oslo_log import helpers as log_helper
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from oslo_log import log as logging
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@ -965,13 +966,9 @@ class _DVRAgentInterfaceMixin(object):
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def create_fip_agent_gw_port_if_not_exists(self, context, network_id,
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host):
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"""Function to return the FIP Agent GW port.
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This function will create a FIP Agent GW port
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if required. If the port already exists, it
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will return the existing port and will not
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create a new one.
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"""
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# TODO(slaweq): add proper constraint on database level to avoid
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# creation of duplicated Floating IP gateway ports for same network and
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# same L3 agent. When this will be done, we can get rid of this lock.
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try:
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l3_agent_db = self._get_agent_by_type_and_host(
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context, const.AGENT_TYPE_L3, host)
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@ -983,32 +980,48 @@ class _DVRAgentInterfaceMixin(object):
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l3_agent_mode = self._get_agent_mode(l3_agent_db)
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if l3_agent_mode == const.L3_AGENT_MODE_DVR_NO_EXTERNAL:
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return
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if l3_agent_db:
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LOG.debug("Agent ID exists: %s", l3_agent_db['id'])
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agent_port = self._get_agent_gw_ports_exist_for_network(
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context, network_id, host, l3_agent_db['id'])
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if not agent_port:
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LOG.info("Floating IP Agent Gateway port does not exist, "
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"creating one")
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port_data = {'tenant_id': '',
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'network_id': network_id,
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'device_id': l3_agent_db['id'],
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'device_owner': const.DEVICE_OWNER_AGENT_GW,
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portbindings.HOST_ID: host,
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'admin_state_up': True,
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'name': ''}
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agent_port = plugin_utils.create_port(
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self._core_plugin, context, {'port': port_data})
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if not agent_port:
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msg = _("Unable to create Floating IP Agent Gateway port")
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raise n_exc.BadRequest(resource='router', msg=msg)
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LOG.debug("Floating IP Agent Gateway port %(gw)s created "
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"for the destination host: %(dest_host)s",
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{'gw': agent_port,
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'dest_host': host})
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if not l3_agent_db:
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return
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lock_name = 'fip-gw-lock-' + network_id + '-' + host
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with lockutils.lock(lock_name, external=True):
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return self._create_fip_agent_gw_port_if_not_exists(
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context, network_id, host, l3_agent_db)
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self._populate_mtu_and_subnets_for_ports(context, [agent_port])
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return agent_port
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def _create_fip_agent_gw_port_if_not_exists(self, context, network_id,
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host, l3_agent_db):
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"""Function to return the FIP Agent GW port.
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This function will create a FIP Agent GW port
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if required. If the port already exists, it
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will return the existing port and will not
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create a new one.
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"""
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LOG.debug("Agent ID exists: %s", l3_agent_db['id'])
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agent_port = self._get_agent_gw_ports_exist_for_network(
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context, network_id, host, l3_agent_db['id'])
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if not agent_port:
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LOG.info("Floating IP Agent Gateway port for network %s "
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"does not exist on host %s. Creating one.",
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network_id, host)
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port_data = {'tenant_id': '',
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'network_id': network_id,
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'device_id': l3_agent_db['id'],
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'device_owner': const.DEVICE_OWNER_AGENT_GW,
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portbindings.HOST_ID: host,
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'admin_state_up': True,
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'name': ''}
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agent_port = plugin_utils.create_port(
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self._core_plugin, context, {'port': port_data})
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if not agent_port:
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msg = _("Unable to create Floating IP Agent Gateway port")
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raise n_exc.BadRequest(resource='router', msg=msg)
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LOG.debug("Floating IP Agent Gateway port %(gw)s created "
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"for the destination host: %(dest_host)s",
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{'gw': agent_port,
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'dest_host': host})
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self._populate_mtu_and_subnets_for_ports(context, [agent_port])
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return agent_port
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def _generate_arp_table_and_notify_agent(self, context, fixed_ip,
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mac_address, notifier):
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