[OVN][RFE] Make use of external ports

[Lucas Alvares Gomes]

The commit [0] in core OVN introduced a new port type called "external". These ports are intended to solve the problem with SR-IOV ports and baremetal booting using the OVN built-in DHCP server.

We should integrate this new port type with networking-ovn.

More info see [0]

[0] https://github.com/ovn-org/ovn/commit/b31c76000bef314b68e776d318d1ce4cf152450b

[Lucas Alvares Gomes (lucasagomes)]

The OVN driver now lives in the neutron repository. Moving this bug to their tracker.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/703376
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=4824a714bfe36fb95e0881d61d8ae56e3422ddc1
Submitter: Zuul
Branch: master

commit 4824a714bfe36fb95e0881d61d8ae56e3422ddc1
Author: Lucas Alvares Gomes <email address hidden>
Date: Mon Jan 20 11:20:29 2020 +0000

    [OVN] Add support for external ports

    This patch is adding support for a new port type called "external" in
    core OVN.

    Prior to this work, when a VM had a SR-IOV port attached to it, OVN itself
    wasn't able to reply to things such as DHCP requests packets since the
    OVS port was skipped. Core OVN then introduced the concept of "external"
    ports which are ports deployed on a different node than the one that the
    VM is running and is able to reply to such requests on behalf of the VM.

    With this patch, when a port with the VNIC type "direct" and no
    "switchdev" capability is created, ovn driver will then create a
    logical port with the type "external" for it and add it to a default
    HA Chassis Group. The port will then get bound to the "master" (higher
    priority) chassis of that group.

    Please note that, as a first step, this patch is creating only one HA
    Chassis Group which *all* external ports will belong to. That means that
    all external ports will be *scheduled onto the same node* (but it's
    HA nevertheless). In the future we should enhance this behavior.

    Change-Id: Ic6c4bb6c584682169f3ebd73105a847b05dddc76
    Closes-Bug: #1841154
    Signed-off-by: Lucas Alvares Gomes <email address hidden>