x/vmware-nsx
Code Issues Proposed changes

Avoid race with udev during ovs agent startup

Browse Source 
After taking down the veth link between the physical bridge and the integration
bridge call udevadm settle to wait for any udev events to be completely
processed by the operating system before recreating the veth pair.

Some distributions (e.g. openSUSE) have udev rules installed by default that
call e.g. ifdown <interface> during the remove event. If that is processed
after the ovs agent already brought up the veth pair again the veth pair's
link will be down after the agent completed startup and networking will be
broken for all VM instances.

Change-Id: I95520ea96a9804c5261a0c994bbca137535cc37c
Closes-Bug: #1218556
This commit is contained in:
Ralf Haferkamp 2013-08-29 20:50:55 +02:00
parent df8b951caf
commit c3c8d1f77a
2 changed files with 19 additions and 1 deletions
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5
neutron/plugins/openvswitch/agent/ovs_neutron_agent.py
View File

@ -32,6 +32,7 @@ from oslo.config import cfg
from neutron.agent import l2population_rpc
from neutron.agent.linux import ip_lib
from neutron.agent.linux import ovs_lib
from neutron.agent.linux import utils
from neutron.agent import rpc as agent_rpc
from neutron.agent import securitygroups_rpc as sg_rpc
from neutron.common import config as logging_config
@ -778,6 +779,10 @@ class OVSNeutronAgent(sg_rpc.SecurityGroupAgentRpcCallbackMixin,
br.delete_port(phys_veth_name)
if ip_lib.device_exists(int_veth_name, self.root_helper):
ip_lib.IPDevice(int_veth_name, self.root_helper).link.delete()
# Give udev a chance to process its rules here, to avoid
# race conditions between commands launched by udev rules
# and the subsequent call to ip_wrapper.add_veth
utils.execute(['/sbin/udevadm', 'settle', '--timeout=10'])
int_veth, phys_veth = ip_wrapper.add_veth(int_veth_name,
phys_veth_name)
self.int_ofports[physical_network] = self.int_br.add_port(int_veth)

15
neutron/tests/unit/openvswitch/test_ovs_neutron_agent.py
View File

@ -23,6 +23,7 @@ import testtools
from neutron.agent.linux import ip_lib
from neutron.agent.linux import ovs_lib
from neutron.agent.linux import utils
from neutron.common import constants as n_const
from neutron.openstack.common.rpc import common as rpc_common
from neutron.plugins.openvswitch.agent import ovs_neutron_agent
@ -327,6 +328,7 @@ class TestOvsNeutronAgent(base.BaseTestCase):
with contextlib.nested(
mock.patch.object(ip_lib, "device_exists"),
mock.patch.object(sys, "exit"),
mock.patch.object(utils, "execute"),
mock.patch.object(ovs_lib.OVSBridge, "remove_all_flows"),
mock.patch.object(ovs_lib.OVSBridge, "add_flow"),
mock.patch.object(ovs_lib.OVSBridge, "add_port"),
@ -337,15 +339,26 @@ class TestOvsNeutronAgent(base.BaseTestCase):
mock.patch.object(ip_lib.IpLinkCommand, "delete"),
mock.patch.object(ip_lib.IpLinkCommand, "set_up"),
mock.patch.object(ip_lib.IpLinkCommand, "set_mtu")
) as (devex_fn, sysexit_fn, remflows_fn, ovs_addfl_fn,
) as (devex_fn, sysexit_fn, utilsexec_fn, remflows_fn, ovs_addfl_fn,
ovs_addport_fn, ovs_delport_fn, br_addport_fn,
br_delport_fn, addveth_fn, linkdel_fn, linkset_fn, linkmtu_fn):
devex_fn.return_value = True
parent = mock.MagicMock()
parent.attach_mock(utilsexec_fn, 'utils_execute')
parent.attach_mock(linkdel_fn, 'link_delete')
parent.attach_mock(addveth_fn, 'add_veth')
addveth_fn.return_value = (ip_lib.IPDevice("int-br-eth1"),
ip_lib.IPDevice("phy-br-eth1"))
ovs_addport_fn.return_value = "int_ofport"
br_addport_fn.return_value = "phys_veth"
self.agent.setup_physical_bridges({"physnet1": "br-eth"})
expected_calls = [mock.call.link_delete(),
mock.call.utils_execute(['/sbin/udevadm',
'settle',
'--timeout=10']),
mock.call.add_veth('int-br-eth',
'phy-br-eth')]
parent.assert_has_calls(expected_calls, any_order=False)
self.assertEqual(self.agent.int_ofports["physnet1"],
"phys_veth")
self.assertEqual(self.agent.phys_ofports["physnet1"],