[ovn]Floating IP adds distributed attributes

[ZhouHeng]

By set config ovn.enable_distributed_floating_ip, we can set whether the floating IP of the entire cluster is distributed or centralized.
There is no way to set a floating IP separately, and the flow of floating IP cannot be finely controlled.

If the backend is ovn, we can set dnat_and_snat's external_mac determines whether it is distributed or centralized, each floating IP can be easily set individually.

[Rodolfo Alonso (rodolfo-alonso-hernandez)]

This could be an interesting feature. However this should be treated as an RFE and discussed in the Neutron drivers meeting. I could need a blueprint or a spec.

[ZhouHeng (zhouhenglc)]

hi rodolfo, I register a bp: https://blueprints.launchpad.net/neutron/+spec/custom-floatingip-distributed

[Akihiro Motoki (amotoki)]

As Rodolfo mentioned, this sounds a kind of feature request. I add the 'rfe' tag so that the neutron drivers team are aware of it.

In the process of feature enhancement in neutron, we first need to discuss a motivation of a feature request and approve a corresponding RFE. A blueprint is optional. More detail on the process is found at https://docs.openstack.org/neutron/latest/contributor/policies/blueprints.html.

Looking at the blueprint you filed, the description is not so long. it would be nice to cover it in the bug description.
We can continue the RFE discussion here.

[ZhouHeng (zhouhenglc)]

Currently, neutron uses ovn ML2 driver and ovn_l3 plugin supports setting the floating IP to distributed. External traffic can go directly to the compute node without passing through the network node, and increases the network performance. This is very useful for the demand for high-performance networks.

However, we decide whether floating ips are distributed or centralized by setting configuration(enable_distributed_floating_ip). This is global. after configuration, all floating ips are centralized or distributed.

The actual use may be complicated:

1.Not all vms with floating ip may require high-performance networks, and may only be exposed to the outside world to provide services.
2.Due to equipment conditions, some compute nodes are not equipped with external network card. If enable distributed, the vm of this compute node cannot allocate floating ip.

I would like to be able to decide whether to be distributed or centralized when creating floating IP, or floating IP is bound to virtual machines, or according to whether the node of the bound vm has distributed conditions.
In this way, I can decide whether floating IP is distributed or centralized according to my vm requirements and hardware conditions.

[Lajos Katona (lajos-katona)]

We discussed this RFE on the Drivers meeting:
https://meetings.opendev.org/meetings/neutron_drivers/2022/neutron_drivers.2022-06-24-14.00.log.html#l-116

The agreement was to the direction to have a new extension for FIP distributed, and make OVN aware of it or perhaps easier and enough to do it only in OVN l3.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/neutron-specs/+/846987
Committed: https://opendev.org/openstack/neutron-specs/commit/94146b6b3cebd7cdee0835d737cab8d9f9245cfe
Submitter: "Zuul (22348)"
Branch: master

commit 94146b6b3cebd7cdee0835d737cab8d9f9245cfe
Author: zhouhenglc <email address hidden>
Date: Mon Jun 27 10:13:46 2022 +0800

    [ovn]Floating IP adds distributed attributes

    Neutron adds distributed attributes to each Floating IP.
    Users can set this attribute according to their actual
    environment and use requirements.

    see more [1]

    [1] https://bugs.launchpad.net/neutron/+bug/1978039

    Related-Bug: #1978039

    Change-Id: Ibdaa0ae502b5fd413cb08e68356e0c18463c4974

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/neutron-lib/+/855053
Committed: https://opendev.org/openstack/neutron-lib/commit/7441b091ee13b22376fbfb970b5372d9d6b4a00c
Submitter: "Zuul (22348)"
Branch: master

commit 7441b091ee13b22376fbfb970b5372d9d6b4a00c
Author: zhouhenglc <email address hidden>
Date: Tue Aug 30 10:36:38 2022 +0800

    [ovn]Floating IP adds distributed attributes

    Partial-bug: #1978039

    Partially-Implements: blueprint custom-floatingip-distributed

    Change-Id: I7894c2b5afa11bcb0c78b3525d74bd9345edd361