nova notifier called 3 times for each port

[Kevin Benton]

The nova notifier is being called 3 different times for each port event due to multiple instantiations of db_base_plugin_v2 each constructing a new notifier and subscribing it to sqlalchemy events. This can be seen in the logs on each event:

2016-09-10 01:25:52.375 14798 DEBUG neutron.notifiers.nova [req-35cf2ca3-edaa-4e88-9551-c106ab84a031 neutron -] Ignoring state change previous_port_status: DOWN current_port_status: DOWN port_id 92aa19ff-c9c9-4771-ad68-ebe1910ba3dc record_port_status_changed /opt/stack/new/neutron/neutron/notifiers/nova.py:223
2016-09-10 01:25:52.376 14798 DEBUG neutron.notifiers.nova [req-35cf2ca3-edaa-4e88-9551-c106ab84a031 neutron -] Ignoring state change previous_port_status: DOWN current_port_status: DOWN port_id 92aa19ff-c9c9-4771-ad68-ebe1910ba3dc record_port_status_changed /opt/stack/new/neutron/neutron/notifiers/nova.py:223
2016-09-10 01:25:52.376 14798 DEBUG neutron.notifiers.nova [req-35cf2ca3-edaa-4e88-9551-c106ab84a031 neutron -] Ignoring state change previous_port_status: DOWN current_port_status: DOWN port_id 92aa19ff-c9c9-4771-ad68-ebe1910ba3dc record_port_status_changed /opt/stack/new/neutron/neutron/notifiers/nova.py:223

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/368631

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/368631
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=dfbc809169da9af7dfc2421244d188caadcada05
Submitter: Jenkins
Branch: master

commit dfbc809169da9af7dfc2421244d188caadcada05
Author: Kevin Benton <email address hidden>
Date: Fri Sep 9 05:12:03 2016 -0700

    Use singleton for Nova notifier

    By adding a singleton getter method and using it in the places
    that use nova notifiers, we ensure that only one object exists
    so all callers share the same batching queues and the sqlalchemy
    events will only be fired once.

    Change-Id: I89752d9c69feb578f0294339aae1a5cf51ec124b
    Closes-Bug: #1622503

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 9.0.0.0rc1 release candidate.