Comment 2 for bug 1778724

Reviewed: https://review.openstack.org/587378
Committed: https://git.openstack.org/cgit/openstack/os-vif/commit/?id=12cea89b91c2548ea544f4e1adf0d346528b6b2e
Submitter: Zuul
Branch: master

commit 12cea89b91c2548ea544f4e1adf0d346528b6b2e
Author: pranabjb <email address hidden>
Date: Tue Jul 31 15:58:10 2018 +0530

    Support for OVS DB TCP socket communication.

    While adding a vif to the ovs bridge(br-int), Nova(os-vif) invokes the
    ovs-vsctl command. This works fine when OVS DB server is listening for
    connections over a UNIX file socket. OVS DB server can listen for connections
    over a TCP socket too [0]. If the OVS DB server is listening over a TCP socket,
    then the ovs-vsctl commands should include the optional argument
    '--db=tcp:ip:port', else vif addition to OVS bridge would fail.
    eg: ovs-vsctl --db=tcp:169.254.1.1:6640 add-port br-int eth0

    This patch adds a new config parameter: 'ovsdb_connection'. By default,
    if ovsdb_connection is set to 'None', communication with OVSDB server would
    happen over the UNIX file socket. If it is set to tcp:IP:Port, ovs-vsctl commands
    would use the '--db=tcp:IP:Port' parameter for communicating over a TCP socket.

    Neutron already supports this feature. The ovsdb_connection parameter is
    configured in openvswitch_agent.ini file. [1]
    [0] http://www.openvswitch.org/support/dist-docs/ovsdb-server.1.html
    [1] https://docs.openstack.org/neutron/pike/configuration/openvswitch-agent.html

    Change-Id: I3b0cadd48fd8823ab2dbec81b2c49dc4d33031ce
    Closes-Bug: 1778724