Neutron-metering-agent failed to get traffic counters after a router moving from one l3-agent to another

[Sergey Belous]

MOS 8.0 env, 1 compute, 3 controllers.

Step to reproduce:
1. Create internal net, subnet, router. Set external gateway for router, add interface to router for created net.
2. Create neutron-meter-label
3. Remove a router from a L3 agent from one controller and add a router to a L3 agent on another controller

After that we can see traces in neutron-meter-agent logs:
2015-12-02 11:02:42.607 26244 DEBUG neutron.agent.linux.utils [-] Running command: ['sudo', 'neutron-rootwrap', '/etc/neutron/rootwrap.conf', 'ip', 'netns', 'exec', 'qrouter-27e416a2-c7fd-4e75-9d94-e6d4c77390ac', 'iptables', '-t', 'filter', '-L', 'neutron-meter-l-b25329ed-e71', '-n', '-v', '-x', '-Z'] create_process /usr/lib/python2.7/dist-packages/neutron/agent/linux/utils.py:85
2015-12-02 11:02:43.334 26244 ERROR neutron.agent.linux.utils [-]
Command: ['sudo', 'neutron-rootwrap', '/etc/neutron/rootwrap.conf', 'ip', 'netns', 'exec', 'qrouter-27e416a2-c7fd-4e75-9d94-e6d4c77390ac', 'iptables', '-t', 'filter', '-L', 'neutron-meter-l-b25329ed-e71', '-n', '-v', '-x', '-Z']
Exit code: 1
Stdin:
Stdout:
Stderr: iptables: No chain/target/match by that name.

2015-12-02 11:02:43.343 26244 ERROR neutron.services.metering.drivers.iptables.iptables_driver [-] Failed to get traffic counters, router: {u'status': u'ACTIVE', u'name': u'router02', u'gw_port_id': u'339e7c19-48ab-4898-ba18-54f6b5ba2c2d', u'admin_state_up': True, u'tenant_id': u'fcab0b76df20485193be7853a28ee929', u'_metering_labels': [{u'rules': [], u'id': u'af03d219-c236-4199-9057-f2f58770db58'}], u'id': u'27e416a2-c7fd-4e75-9d94-e6d4c77390ac'}
2015-12-02 11:02:43.343 26244 ERROR neutron.services.metering.drivers.iptables.iptables_driver Traceback (most recent call last):
2015-12-02 11:02:43.343 26244 ERROR neutron.services.metering.drivers.iptables.iptables_driver File "/usr/lib/python2.7/dist-packages/neutron/services/metering/drivers/iptables/iptables_driver.py", line 354, in get_traffic_counters
2015-12-02 11:02:43.343 26244 ERROR neutron.services.metering.drivers.iptables.iptables_driver chain, wrap=False, zero=True)
2015-12-02 11:02:43.343 26244 ERROR neutron.services.metering.drivers.iptables.iptables_driver File "/usr/lib/python2.7/dist-packages/neutron/agent/linux/iptables_manager.py", line 720, in get_traffic_counters
2015-12-02 11:02:43.343 26244 ERROR neutron.services.metering.drivers.iptables.iptables_driver current_table = self.execute(args, run_as_root=True)
2015-12-02 11:02:43.343 26244 ERROR neutron.services.metering.drivers.iptables.iptables_driver File "/usr/lib/python2.7/dist-packages/neutron/agent/linux/utils.py", line 159, in execute
2015-12-02 11:02:43.343 26244 ERROR neutron.services.metering.drivers.iptables.iptables_driver raise RuntimeError(m)
2015-12-02 11:02:43.343 26244 ERROR neutron.services.metering.drivers.iptables.iptables_driver RuntimeError:
2015-12-02 11:02:43.343 26244 ERROR neutron.services.metering.drivers.iptables.iptables_driver Command: ['sudo', 'neutron-rootwrap', '/etc/neutron/rootwrap.conf', 'ip', 'netns', 'exec', 'qrouter-27e416a2-c7fd-4e75-9d94-e6d4c77390ac', 'iptables', '-t', 'filter', '-L', 'neutron-meter-l-b25329ed-e71', '-n', '-v', '-x', '-Z']
2015-12-02 11:02:43.343 26244 ERROR neutron.services.metering.drivers.iptables.iptables_driver Exit code: 1
2015-12-02 11:02:43.343 26244 ERROR neutron.services.metering.drivers.iptables.iptables_driver Stdin:
2015-12-02 11:02:43.343 26244 ERROR neutron.services.metering.drivers.iptables.iptables_driver Stdout:
2015-12-02 11:02:43.343 26244 ERROR neutron.services.metering.drivers.iptables.iptables_driver Stderr: iptables: No chain/target/match by that name.

The problem is, that in router's namespace on new controller there are not any rules in iptables, that was created on router's namespace on previous controller by neutron-metering-agent. And neutron-metering-agent not handle it.

[Bug Checker Bot (bug-checker)]

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[Alexander Ignatov (aignatov)]

Low bug is moving to next release.

[Sergey Belous (sbelous)]

The upstream bug: https://bugs.launchpad.net/neutron/+bug/1572548