Description of problem:
An Exception was raised when the following router, connected to a provider-vlan network, was created:
TASK [create router for provider-vlan] ***************************************
task path: /root/bgp-playbooks-templates/playbooks/frrempest.yml:191            
changed: [undercloudbgp-0] => {"changed": true, "router": {"admin_state_up": true, "availability_zone_hints": [], "availability_zones": [], "created_at": "2022-11-10T14:22:03Z", "description": "", "external_gateway_info": {"enable_snat":
true, "external_fixed_ips": [{"ip_address": "172.24.200.92", "subnet_id": "ce0620c8-8dae-42a8-b61b-3ba3c6b89eaa"}, {"ip_address": "2001:db9::f816:3eff:fe19:d969", "subnet_id": "b1b35c3f-879a-4ccf-b9f8-6691c861bb12"}], "network_id": "30b18c76-c4c3-4d60-a601-b97d840a527a"}, "id": "aa6e811b-5e93-4884-aa5b-8696bcd38b38", "name": "router-vlan", "project_id": "29cae679482745afbc9b1851d85ee6b6", "revision_number": 3, "routes": [], "status": "ACTIVE", "tags": [], "tenant_id": "29cae679482745afbc9b1851d85ee6b6", "updated_at": "2022-11-10T14:22:04Z"}}


As you can see, the task finishes successfully, but the ovn-bgp-agent throws and exception.
/var/log/containers/stdouts/ovn_bgp_agent.log.1@ctrl-1-0
----------------------------------------------------------
2022-11-10T14:22:05.668363568+00:00 stdout F 2022-11-10 14:22:05.668 99396 DEBUG ovsdbapp.backend.ovs_idl.event [-] Matched UPDATE: TenantPortCreatedEvent(events=('update',), table='Port_Binding', conditions=None, old_conditions=None) to 
row=Port_Binding(mac=['fa:16:3e:19:d9:69 172.24.200.92/24 2001:db9::f816:3eff:fe19:d969/64'], nat_addresses=[], type=chassisredirect, virtual_parent=[], up=[True], options={'always-redirect': 'true', 'distributed-port': 'lrp-33f102ea-03ed
-41fd-b35a-c7695918ee19'}, parent_port=[], external_ids={'neutron:network_name': 'neutron-30b18c76-c4c3-4d60-a601-b97d840a527a', 'neutron:revision_number': '1', 'neutron:router_name': 'aa6e811b-5e93-4884-aa5b-8696bcd38b38', 'neutron:subne
t_ids': 'ce0620c8-8dae-42a8-b61b-3ba3c6b89eaa b1b35c3f-879a-4ccf-b9f8-6691c861bb12'}, tag=[], encap=[], chassis=[<ovs.db.idl.Row object at 0x7f5c515b4790>], datapath=0222d076-ed25-4f82-9678-cafbcc418186, gateway_chassis=[], tunnel_key=2, 
logical_port=cr-lrp-33f102ea-03ed-41fd-b35a-c7695918ee19, requested_chassis=[]) old=Port_Binding(up=[False], chassis=[]) matches /usr/lib/python3.9/site-packages/ovsdbapp/backend/ovs_idl/event.py:43ESC[00m
2022-11-10T14:22:05.668897688+00:00 stdout F 2022-11-10 14:22:05.668 99396 DEBUG ovsdbapp.backend.ovs_idl.event [-] Matched UPDATE: PortBindingChassisCreatedEvent(events=('update',), table='Port_Binding', conditions=None, old_conditions=N
one) to row=Port_Binding(mac=['fa:16:3e:19:d9:69 172.24.200.92/24 2001:db9::f816:3eff:fe19:d969/64'], nat_addresses=[], type=chassisredirect, virtual_parent=[], up=[True], options={'always-redirect': 'true', 'distributed-port': 'lrp-33f10
2ea-03ed-41fd-b35a-c7695918ee19'}, parent_port=[], external_ids={'neutron:network_name': 'neutron-30b18c76-c4c3-4d60-a601-b97d840a527a', 'neutron:revision_number': '1', 'neutron:router_name': 'aa6e811b-5e93-4884-aa5b-8696bcd38b38', 'neutr
on:subnet_ids': 'ce0620c8-8dae-42a8-b61b-3ba3c6b89eaa b1b35c3f-879a-4ccf-b9f8-6691c861bb12'}, tag=[], encap=[], chassis=[<ovs.db.idl.Row object at 0x7f5c515b4790>], datapath=0222d076-ed25-4f82-9678-cafbcc418186, gateway_chassis=[], tunnel
_key=2, logical_port=cr-lrp-33f102ea-03ed-41fd-b35a-c7695918ee19, requested_chassis=[]) old=Port_Binding(up=[False], chassis=[]) matches /usr/lib/python3.9/site-packages/ovsdbapp/backend/ovs_idl/event.py:43ESC[00m
2022-11-10T14:22:05.669418224+00:00 stdout F 2022-11-10 14:22:05.669 99396 DEBUG oslo_concurrency.lockutils [-] Lock "bgp" acquired by "ovn_bgp_agent.drivers.openstack.ovn_bgp_driver.OVNBGPDriver.expose_ip" :: waited 0.000s inner /usr/lib
...
2022-11-10T14:22:06.107510357+00:00 stdout F 2022-11-10 14:22:06.107 99396 DEBUG oslo_concurrency.lockutils [-] Lock "bgp" released by "ovn_bgp_agent.drivers.openstack.ovn_bgp_driver.OVNBGPDriver.expose_ip" :: held 0.438s inner /usr/lib/python3.9/site-packages/oslo_concurrency/lockutils.py:367ESC[00m
2022-11-10T14:22:06.108992207+00:00 stdout F 2022-11-10 14:22:06.107 99396 ERROR ovsdbapp.event [-] Unexpected exception in notify_loop: KeyError: 'object does not exists'                                                                  
2022-11-10T14:22:06.108992207+00:00 stdout F 2022-11-10 14:22:06.107 99396 ERROR ovsdbapp.event Traceback (most recent call last):                                                                                                           
2022-11-10T14:22:06.108992207+00:00 stdout F 2022-11-10 14:22:06.107 99396 ERROR ovsdbapp.event   File "/usr/lib/python3.9/site-packages/ovsdbapp/event.py", line 159, in notify_loop                                                        
2022-11-10T14:22:06.108992207+00:00 stdout F 2022-11-10 14:22:06.107 99396 ERROR ovsdbapp.event     match.run(event, row, updates)                                                                                                           
2022-11-10T14:22:06.108992207+00:00 stdout F 2022-11-10 14:22:06.107 99396 ERROR ovsdbapp.event   File "/usr/lib/python3.9/site-packages/ovn_bgp_agent/drivers/openstack/watchers/bgp_watcher.py", line 52, in run                           
2022-11-10T14:22:06.108992207+00:00 stdout F 2022-11-10 14:22:06.107 99396 ERROR ovsdbapp.event     self.agent.expose_ip(ips, row)                                                                                                           
2022-11-10T14:22:06.108992207+00:00 stdout F 2022-11-10 14:22:06.107 99396 ERROR ovsdbapp.event   File "/usr/lib/python3.9/site-packages/oslo_concurrency/lockutils.py", line 360, in inner                                                  
2022-11-10T14:22:06.108992207+00:00 stdout F 2022-11-10 14:22:06.107 99396 ERROR ovsdbapp.event     return f(*args, **kwargs)                                                                                                                
2022-11-10T14:22:06.108992207+00:00 stdout F 2022-11-10 14:22:06.107 99396 ERROR ovsdbapp.event   File "/usr/lib/python3.9/site-packages/ovn_bgp_agent/drivers/openstack/ovn_bgp_driver.py", line 480, in expose_ip                          
2022-11-10T14:22:06.108992207+00:00 stdout F 2022-11-10 14:22:06.107 99396 ERROR ovsdbapp.event     self._expose_ip(ips, row, associated_port)                                                                                               
2022-11-10T14:22:06.108992207+00:00 stdout F 2022-11-10 14:22:06.107 99396 ERROR ovsdbapp.event   File "/usr/lib/python3.9/site-packages/ovn_bgp_agent/drivers/openstack/ovn_bgp_driver.py", line 597, in _expose_ip                         
2022-11-10T14:22:06.108992207+00:00 stdout F 2022-11-10 14:22:06.107 99396 ERROR ovsdbapp.event     linux_net.add_ip_route(                                                                                                                  
2022-11-10T14:22:06.108992207+00:00 stdout F 2022-11-10 14:22:06.107 99396 ERROR ovsdbapp.event   File "/usr/lib/python3.9/site-packages/ovn_bgp_agent/utils/linux_net.py", line 492, in add_ip_route                                        
2022-11-10T14:22:06.108992207+00:00 stdout F 2022-11-10 14:22:06.107 99396 ERROR ovsdbapp.event     oif = ndb.interfaces[oif_name]['index']                                                                                                  
2022-11-10T14:22:06.108992207+00:00 stdout F 2022-11-10 14:22:06.107 99396 ERROR ovsdbapp.event   File "/usr/lib/python3.9/site-packages/pr2modules/ndb/auth_manager.py", line 69, in guard                                                  
2022-11-10T14:22:06.108992207+00:00 stdout F 2022-11-10 14:22:06.107 99396 ERROR ovsdbapp.event     return f(obj, *argv, **kwarg)                                                                                                            
2022-11-10T14:22:06.108992207+00:00 stdout F 2022-11-10 14:22:06.107 99396 ERROR ovsdbapp.event   File "/usr/lib/python3.9/site-packages/pr2modules/ndb/main.py", line 557, in __getitem__                                                   
2022-11-10T14:22:06.108992207+00:00 stdout F 2022-11-10 14:22:06.107 99396 ERROR ovsdbapp.event     ret = self.template(key, table)                                                                                                          
2022-11-10T14:22:06.108992207+00:00 stdout F 2022-11-10 14:22:06.107 99396 ERROR ovsdbapp.event   File "/usr/lib/python3.9/site-packages/pr2modules/ndb/main.py", line 394, in template                                                      
2022-11-10T14:22:06.108992207+00:00 stdout F 2022-11-10 14:22:06.107 99396 ERROR ovsdbapp.event     return iclass(self,
2022-11-10T14:22:06.108992207+00:00 stdout F 2022-11-10 14:22:06.107 99396 ERROR ovsdbapp.event   File "/usr/lib/python3.9/site-packages/pr2modules/ndb/objects/interface.py", line 431, in __init__                                         
2022-11-10T14:22:06.108992207+00:00 stdout F 2022-11-10 14:22:06.107 99396 ERROR ovsdbapp.event     super(Interface, self).__init__(*argv, **kwarg)
2022-11-10T14:22:06.108992207+00:00 stdout F 2022-11-10 14:22:06.107 99396 ERROR ovsdbapp.event   File "/usr/lib/python3.9/site-packages/pr2modules/ndb/objects/__init__.py", line 327, in __init__
2022-11-10T14:22:06.108992207+00:00 stdout F 2022-11-10 14:22:06.107 99396 ERROR ovsdbapp.event     raise KeyError('object does not exists')
2022-11-10T14:22:06.108992207+00:00 stdout F 2022-11-10 14:22:06.107 99396 ERROR ovsdbapp.event KeyError: 'object does not exists'
2022-11-10T14:22:06.108992207+00:00 stdout F 2022-11-10 14:22:06.107 99396 ERROR ovsdbapp.event ESC[00m





This is the task that reproduces this bug:
  - name: create router for provider-vlan
    openstack.cloud.router:
      cloud: overcloud
      name: router-vlan
      state: present
      network: provider-vlan
      interfaces:
        - private-vlan-subnet
        - private-vlan-subnet-ipv6