Comment 4 for bug 1712517

Reviewed: https://review.openstack.org/496707
Committed: https://git.openstack.org/cgit/openstack/os-net-config/commit/?id=77fe5922bd7ca5c2a199d383b03537c08edfcc1c
Submitter: Jenkins
Branch: stable/pike

commit 77fe5922bd7ca5c2a199d383b03537c08edfcc1c
Author: Jakub Libosvar <email address hidden>
Date: Mon Aug 21 16:21:12 2017 +0000

    Delete controller for standalone OVS bridges

    The patch adds an OVS extra parameter to delete controller for bridges
    configured with standalone fail mode. By default, bridges are created
    without having an openflow controllers. If node is restarted, the bridge
    is set to standalone mode but if a service managing the bridge sets a
    controller, it will remain in the ovsdb.

    As ovs-vswitchd sets the bridge behavior to normal MAC learning switch
    only if bridge in standalone mode can't communicate with its controller,
    leaving controller defined can cause node outage when bridge is used as
    management network. In such case controller service, like
    neutron-openvswitch-agent, would need to communicate over management
    network but given that bridge is in standalone mode but communicates
    with controller, management network won't be reachable. This creates a
    chicken-egg problem.

    By removing controller by default, ovs-vswitchd implements a normal
    action rule to the standalone bridge and service can use the bridge as
    management network and eventually set the brdige to secure and set the
    flows manually.

    See opened Bugzilla for more information:
    https://bugzilla.redhat.com/show_bug.cgi?id=1473763

    Closes-bug: #1712517

    Change-Id: Iad48312667834ea8f5c7145595ae89cb5159b36d
    (cherry picked from commit f8d76d2cdebfa0d06233a59a8f6539207c5b5a4e)