metering-agent failed to get traffic counters when no router-namespace where meter-label-rules were added

[Sergey Belous]

Removing router from l3 agent cause errors from neutron-metering-agent. The neutron-meter-agent continues try to get traffic counters from iptables on router-namespace, which is not exist after removing router from l3-agent.

Steps 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. Use 'neutron l3-agent-router-remove' command to remove a router from a L3 agent
Trace in neutron-metering-agent logs:
2016-04-20 12:28:26.699 ERROR neutron.agent.linux.utils [-] Exit code: 1; Stdin: ; Stdout: ; Stderr: Cannot open network namespace "qrouter-c8acd926-88e5-4292-883e-e928fb3f6d32": No such file or directory

2016-04-20 12:28:26.700 ERROR neutron.services.metering.drivers.iptables.iptables_driver [-] Failed to get traffic counters, router: {u'status': u'ACTIVE', u'name': u'router05', u'gw_port_id': u'f36b30d3-5290-4896-837c-108b8cd4f3dc', u'admin_state_up': True, u'tenant_id': u'1c0eb24bdbb1406bb7d1346f36064ebd', u'_metering_labels': [{u'rules': [{u'remote_ip_prefix': u'0.0.0.0/0', u'direction': u'egress', u'metering_label_id': u'67dae290-38cb-4962-80ab-d6d3404dc6df', u'id': u'799f3361-6f90-4e36-a338-311d6e7c9d5b', u'excluded': False}], u'id': u'67dae290-38cb-4962-80ab-d6d3404dc6df'}], u'id': u'c8acd926-88e5-4292-883e-e928fb3f6d32'}
2016-04-20 12:28:26.700 TRACE neutron.services.metering.drivers.iptables.iptables_driver Traceback (most recent call last):
2016-04-20 12:28:26.700 TRACE neutron.services.metering.drivers.iptables.iptables_driver File "/opt/stack/neutron/neutron/services/metering/drivers/iptables/iptables_driver.py", line 355, in get_traffic_counters
2016-04-20 12:28:26.700 TRACE neutron.services.metering.drivers.iptables.iptables_driver chain, wrap=False, zero=True)
2016-04-20 12:28:26.700 TRACE neutron.services.metering.drivers.iptables.iptables_driver File "/opt/stack/neutron/neutron/agent/linux/iptables_manager.py", line 712, in get_traffic_counters
2016-04-20 12:28:26.700 TRACE neutron.services.metering.drivers.iptables.iptables_driver current_table = self.execute(args, run_as_root=True)
2016-04-20 12:28:26.700 TRACE neutron.services.metering.drivers.iptables.iptables_driver File "/opt/stack/neutron/neutron/agent/linux/utils.py", line 137, in execute
2016-04-20 12:28:26.700 TRACE neutron.services.metering.drivers.iptables.iptables_driver raise RuntimeError(msg)
2016-04-20 12:28:26.700 TRACE neutron.services.metering.drivers.iptables.iptables_driver RuntimeError: Exit code: 1; Stdin: ; Stdout: ; Stderr: Cannot open network namespace "qrouter-c8acd926-88e5-4292-883e-e928fb3f6d32": No such file or directory
2016-04-20 12:28:26.700 TRACE neutron.services.metering.drivers.iptables.iptables_driver
2016-04-20 12:28:26.700 TRACE neutron.services.metering.drivers.iptables.iptables_driver

[Hunt Xu (huntxu)]

Hi Sergey,
I have also encountered this problem and worked out a patch. If you are not currently working on this, could you please assign this bug to me?

[Sergey Belous (sbelous)]

HuntXu, yep, sure. I can't assign this bug to you, but I can remove me from assignee and then you can assign this bug to yourself.

[Sergey Belous (sbelous)]

Can you please also check, is it related problem and can it [1] fix the problem with metering agent?

[1] https://review.openstack.org/#/c/309050/

[Hunt Xu (huntxu)]

Unfortunately iptables_manager does not use ip_lib to run the commands, so [1] could not fix this problem.

[1] https://review.openstack.org/#/c/309050/

[OpenStack Infra (hudson-openstack)]

Change abandoned by Hunt Xu (<email address hidden>) on branch: master
Review: https://review.openstack.org/316622

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/316688

[OpenStack Infra (hudson-openstack)]

Change abandoned by Armando Migliaccio (<email address hidden>) on branch: master
Review: https://review.openstack.org/316688
Reason: This review is > 4 weeks without comment, and failed Jenkins the last time it was checked. We are abandoning this for now. Feel free to reactivate the review by pressing the restore button and leaving a 'recheck' comment to get fresh test results.

[Armando Migliaccio (armando-migliaccio)]

Needs a new owner.

[Rodolfo Alonso (rodolfo-alonso-hernandez)]

Bug closed due to lack of activity, please feel free to reopen if needed.