[ovn-octavia-provider] Member with FIP not reachable

[Mohammed Naser]

We've noticed the following issue with the OVN octavia provider and we've narrowed it down to the following:

- Member with floating IP not reachable through load balancer

We've noticed that at first, it loses all connectivity. Once the floating IP gets removed and added, the VM will gain connectivity directly. However, that member will continue to be unreachable via the load balancer (but other members without floating IPs will work).

DVR is enabled in this case.

[Fernando Royo (froyoredhat)]

Hi,

I assume that your LB is also using a FIP attached to LB VIP, and that case is a known limitation.
When Load Balancer and its member has FIP assigned and environment is configured to use DVR the member FIP needs to be centralized. It is current core OVN limitation and doesn't look is will be fixed soon as last time it was addressed we get this feedback:

"don't think we can resolve this issue. If a LB VIP has FIP, then the traffic from North -> South needs
to be load balanced and unless it is centralized on gateway node, we cannnot do load balancing."

Confirm that this is your env context "FIP attached to LB VIP and the Member also with FIP attached".

[Cristian Contescu (ckristi)]

Hi Fernando,

So, let me see if I understand this correctly, given this (very simplistic representation of the) setup:

```
North/Internet <------> (Octavia OVN loadbalancer + listener + pool; (VIP with floating IP attached )
                                                         <------> Member1 (VM1)
                                                         <------> Member2 (VM2)
                                                         <------> Member3 (VM3 with a FIP attached prior to becoming an LB member)
```

it is always expected for the Member3 to not be reachable (at least until the VM3 floating IP is removed)?

I am asking since this seems to be matching the issue described by Mohammed in this ticket as well: https://bugs.launchpad.net/neutron/+bug/2059716

Thank you for the clarifications.

All the best,
Cristi