devstack should support IPv6 tunnel endpoints

[Brian Haley]

Changes were merged a year or more ago in devstack to support running all
services using IPv6 endpoints (SERVICE_IP_VERSION=6). Tunnel endpoint
support was one of the only things left at IPv4 because, at the time,
neither OVS nor Linuxbridge drivers supported it (see local_ip in
ml2_conf.ini).

Now that support has been merged in Neutron, we should support using
it in devstack, just needs a little tweaking to TUNNEL_ENDPOINT_IP.

[Sean Dague (sdague)]

No reviews found in this bug, unassigning. Please add a comment with active reviews before assigning an individual, or tag the bug in the gerrit review, which will do that automatically

[Brian Haley (brian-haley)]

I actually created https://review.opendev.org/c/openstack/devstack/+/710519 for this but forgot to put a closes-bug tag in the commit message. I just added it a minute ago since it hasn't merged yet.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/devstack/+/710519
Committed: https://opendev.org/openstack/devstack/commit/c869d59857c636d21ecd0329023038b24252627d
Submitter: "Zuul (22348)"
Branch: master

commit c869d59857c636d21ecd0329023038b24252627d
Author: Brian Haley <email address hidden>
Date: Fri Feb 28 14:55:08 2020 -0500

    Add support for IPv6 tunnel endpoints

    Currently, neutron tunnel endpoints must be IPv4 addresses,
    i.e. $HOST_IP, although IPv6 endpoints are supported by most
    drivers.

    Create a TUNNEL_IP_VERSION variable to choose which host IP
    to use, either HOST_IP or HOST_IPV6, and configure it in the
    OVS and Linuxbridge agent driver files. The default is still
    IPv4, but it can be over-ridden by specifying TUNNEL_ENDPOINT_IP
    accordingly.

    This behaves similar to the SERVICE_IP_VERSION option, which
    can either be set to 4 or 6, but not 4+6 - the tunnel overhead
    should be consistent on all systems in order not to have MTU
    issues.

    Must set the ML2 overlay_ip_version config option to match
    else agent tunnel sync RPC will not work.

    Must set the OVN external_ids:ovn-encap-ip config option to
    the correct address.

    Updated 'devstack-ipv6-only' job definition and verification role
    that will set all services and tunnels to use IPv6 addresses.

    Closes-bug: #1619476

    Change-Id: I6034278dfc17b55d7863bc4db541bbdaa983a686