[OVN] support update fixed_ips of metadata port

[Liu Xie]

In some scenarios, the customers want to modify the fixed_ips of metadata port.
We can workaround it by follow steps:

1.Fisrt, update fixed_ips of metaadta_port:
neutron port-update --fixed-ip subnet_id=e130a5c7-6f47-4c76-b245-cf05369f2161,ip_address=192.168.111.16 460dffa9-e25a-437d-8252-ae9c5185aaab

2.Then, only trigger subnet updated:
neutron subnet-update --enable-dhcp e130a5c7-6f47-4c76-b245-cf05369f2161

3.Finally restart neutron-ovn-metadata-agent

I think it is a good requirement that support update fixed_ips of metadata port. Maybe we can implement it in neutron-ovn-metadata-agent that watching the UPDATE event of port_bidnings, and then update_datapath if row is related to metadata port.

[huanghailun (lnun)]

We can update neutron-ovn-metadata-agent, add the port_binding update event of monitoring localport tpye, and judge if the neutron:cidrs field in the external_ids of port_binding table has changed, then update_datapath.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/neutron/+/864715

[huanghailun (lnun)]

The classless_static_route of DHCP_Options options fields also needs to be updated.
https://bugs.launchpad.net/neutron/+bug/1942794

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/neutron/+/864715
Committed: https://opendev.org/openstack/neutron/commit/686698284b3553001398f65614c6521359bc45aa
Submitter: "Zuul (22348)"
Branch: master

commit 686698284b3553001398f65614c6521359bc45aa
Author: hailun.huang <email address hidden>
Date: Wed Nov 16 09:35:22 2022 +0000

    Update tap ip in metadata agent when metadata port ip updated

    Update neutron-ovn-metadata-agent, catch port_binding update event
    of monitoring localport type, and judge if the neutron:cidrs field in
    the external_ids of port_binding table has changed,
    then update_datapath.

    Closes-Bug: #1996677
    Change-Id: Ibdc1b385b07a2ab1ca8e4b6278f6d39fb5839509

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 22.0.0.0rc1 release candidate.