Remove LB from LS belonging to provider networks

In core OVN, LBs on switches with localnet ports (i.e., neutron
provider networks) don't work if traffic comes from localnet [1]

In order to force NAT to happen at the virtual router instead
of the LS level, when the VIP of the LoadBalancer is associated
to a provider network we should avoid adding the LB to the
LS associated to the provider network

TODO:
- Open Launchpad bug
- Fix unittesting

[1] https://bugzilla.redhat.com/show_bug.cgi?id=2164652

Change-Id: I009ddd2604d208bbf793e2d19d4195b77726f7b2

ovn_octavia_provider/helper.py

@@ -18,6 +18,7 @@ import re
 import threading
 
 import netaddr
+from neutron_lib.api.definitions import external_net
 from neutron_lib import constants as n_const
 from neutronclient.common import exceptions as n_exc
 from octavia_lib.api.drivers import data_models as o_datamodels
@@ -989,11 +990,16 @@ class OvnProviderHelper():
                 loadbalancer[constants.ID],
                 protocol=protocol)
             ovn_lb = ovn_lb if protocol else ovn_lb[0]
-            # NOTE(froyo): This is the association of the lb to the VIP ls
-            # so this is executed right away
-            self._update_lb_to_ls_association(
-                ovn_lb, network_id=port['network_id'],
-                associate=True, update_ls_ref=True)
+
+            # NOTE(ltomasbo): If the VIP is on a provider network, it does
+            # not need to be associated to its LS
+            network = neutron_client.show_network(port['network_id'])
+            if not network.get(external_net.PHYSICAL_NETWORK, False):
+                # NOTE(froyo): This is the association of the lb to the VIP ls
+                # so this is executed right away
+                self._update_lb_to_ls_association(
+                    ovn_lb, network_id=port['network_id'],
+                    associate=True, update_ls_ref=True)
             ls_name = utils.ovn_name(port['network_id'])
             ovn_ls = self.ovn_nbdb_api.ls_get(ls_name).execute(
                 check_error=True)