[LB] Linux Bridge agent always loads trunk extension, regardless of the loaded service plugins

[Rodolfo Alonso]

Linux Bridge agent always loads trunk extension, regardless of the loaded service plugins. The trunk agent extension execute unnecessary operations that slows down the agent execution.

For example: https://storage.gra.cloud.ovh.net/v1/AUTH_dcaab5e32b234d56b626f72581e3644c/zuul_opendev_logs_ea7/792505/3/check/neutron-fullstack-with-uwsgi_6/ea75d31/controller/logs/dsvm-fullstack-logs/TestUninterruptedConnectivityOnL2AgentRestart.test_l2_agent_restart_LB%2CFlat-network_/neutron-linuxbridge-agent--2021-05-25--08-56-07-279444_log.txt

A new port is added. The trunk agent extension receives those events a executes the port processing:
2021-05-25 08:56:17.731 107232 DEBUG neutron_lib.callbacks.manager [req-58c1c8d4-c2a9-431c-a2a0-46f80be0e835 - - - - -] Notify callbacks ['neutron.services.trunk.drivers.linuxbridge.agent.driver.LinuxBridgeTrunkDriver.agent_port_change-145314'] for port_device, after_update _notify_loop /home/zuul/src/opendev.org/openstack/neutron/.tox/dsvm-fullstack-gate/lib/python3.8/site-packages/neutron_lib/callbacks/manager.py:192

...

2021-05-25 08:56:17.788 107232 DEBUG oslo_concurrency.lockutils [req-58c1c8d4-c2a9-431c-a2a0-46f80be0e835 - - - - -] Acquired lock "trunk-tapdd335ce5-14" lock /home/zuul/src/opendev.org/openstack/neutron/.tox/dsvm-fullstack-gate/lib/python3.8/site-packages/oslo_concurrency/lockutils.py:266

This lock is released at:
2021-05-25 08:56:17.829 107232 DEBUG oslo_concurrency.lockutils [req-58c1c8d4-c2a9-431c-a2a0-46f80be0e835 - - - - -] Releasing lock "trunk-tapdd335ce5-14" lock /home/zuul/src/opendev.org/openstack/neutron/.tox/dsvm-fullstack-gate/lib/python3.8/site-packages/oslo_concurrency/lockutils.py:282

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/neutron/+/796008

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/neutron/+/796008
Committed: https://opendev.org/openstack/neutron/commit/817d807e9dd6e7b0d1da46342e12f6392d9372ce
Submitter: "Zuul (22348)"
Branch: master

commit 817d807e9dd6e7b0d1da46342e12f6392d9372ce
Author: Rodolfo Alonso Hernandez <email address hidden>
Date: Fri Jun 11 13:26:53 2021 +0000

    Load Linux Bridge Trunk extension if service plugin configured

    Load the Linux Driver Trunk agent extension driver only if the service
    plugin is enabled. If the service plugin is not enabled, the agent
    extension will not subscribe to the port events.

    Change-Id: I883abb5ef122ac7f8fb029d0334fa2d68893f8aa
    Closes-Bug: #1930443

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 19.0.0.0rc1 release candidate.