Convert OVS os-vif driver to use native Python bindings

[sean mooney]

Today os-vif uses ovs-vsctl via processutils. This spawns a new shell for every invocation and repeatedly dumps the ovsdb into memory which is both inefficient and slow. OVS has native Python binding for configuring the ovsdb which would allow us to avoid these issues.

The OVS plugin should be rewritten to leverage the native python bindings
to improve performance, reduce memory footprint and improve security by reducing use of processutils.

[sean mooney (sean-k-mooney)]

investigate using new ovsdbapp lib for this as neutron will be moving to it in the future
https://github.com/openstack/ovsdbapp/

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/476612

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/482226

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/476612
Committed: https://git.openstack.org/cgit/openstack/os-vif/commit/?id=7bfb01bcb151087d70df115ba01f789a8a7f161f
Submitter: Zuul
Branch: master

commit 7bfb01bcb151087d70df115ba01f789a8a7f161f
Author: Rodolfo Alonso Hernandez <“<email address hidden>”>
Date: Thu Sep 20 16:22:00 2018 +0100

    Add abstract OVSDB API

    Abstract all existing 'ovs-vsctl' calls to an abstract OVSDB API.
    This will allow the future addition of a native OVSDB protocol
    implementation of the API without breaking backwards compatibility.

    Partial-Bug: #1666917
    Change-Id: I9ec36be390d713a928a673191008612f3fddad8f

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/482226
Committed: https://git.openstack.org/cgit/openstack/os-vif/commit/?id=1546d349b1656bc98286af47f1e2748b76743abc
Submitter: Zuul
Branch: master

commit 1546d349b1656bc98286af47f1e2748b76743abc
Author: Rodolfo Alonso Hernandez <email address hidden>
Date: Fri Sep 21 10:00:35 2018 +0100

    Add native implementation OVSDB API

    Added native implementation OVSDB API. Both APIs may be enabled
    via configuration file. The default one is the CLI vsctl.

    A new configuration variable, ``ovsdb_connection``, is added to
    define the connection string for the OVSDB backend.

    Added functional tests to vif_plug_ovs. This commit also includes
    the base functions to execute functional tests and a set of them
    to test the OVSDB APIs: native and ovs-vsctl.

    Closes-Bug: #1666917
    Change-Id: I86fbf8c67572e51889eb091d7bff7f9350b52481

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/os-vif 1.15.0 release.