ovs plugin generating the same endpoint number

[Mathieu Rohon]

I'm using the OVS plugin with tunneling in a multi-agent environnement, with devstack.

Once, when I started several ovs agent at the time, the same endpoint number was provisionned for two different IP in the table ovs_tunnel_endpoint.

[Mark McClain (markmcclain)]

What release of OpenStack Network are you running?

[Mathieu Rohon (mathieu-rohon)]

I'm working with the master branch. This bug seems quite hard to duplicate!!

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/27818

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/27818
Committed: http://github.com/openstack/neutron/commit/658452478fb35f3200e5d62b23d328be72d35039
Submitter: Jenkins
Branch: master

commit 658452478fb35f3200e5d62b23d328be72d35039
Author: Roman Podolyaka <email address hidden>
Date: Tue Apr 30 15:12:15 2013 +0300

    Fix a race condition in add_tunnel_endpoint()

    If there are multiple OVS agents concurrently executing
    'tunnel_sync' RPC call a race condition can occur
    leading to insertion of two different TunnelEndpoint
    entries having the same 'id' value.

    Unfortunately, we can not rely on:
      - @lockutils.synchronized(), because a Neutron installation can use
        more than one API node
      - with_lockmode('update'), because it works differently in PostgreSQL
        comparing to MySQL and doesn't guarantee that no new rows have been
        added to the table since the select query was issued. Please take a
        look at http://www.postgresql.org/files/developer/concurrency.pdf for
        more details.

    The proposed fix:
      - ensures there is a unique constraint set for 'id' column
      - wraps creation of a new TunnelEndpoint entry into a
        repeatedly executed transactional block (so even if a concurrent
        DB transaction has been flushed or commited earlier than this one
        we can handle an integrity error and try again, in spite of the
        specified transactions isolation level value)

    Fixes bug 1167916

    Change-Id: I62dc729d595f090436199d5e1b6b98a884ead7a5

[Byron McCollum (byron-mccollum)]

Grizzly backport would be much appreciated!