+++ This bug was initially created as a clone of Bug #1761389 +++
Description of problem:
If we attach a subnet to that external network afterwards, the northbound
database loses that logical port, together with the row in the gateway_chassis table.
Version-Release number of selected component (if applicable):
OSP13 (all versions)
Steps to Reproduce:
openstack network create public --external --default --provider-network-type vlan --provider-physical-network tenant --provider-segment 1099
openstack router create myrouter
EXT_NET_ID=$(openstack network show public -f value -c id)
openstack router set --external-gateway $EXT_NET_ID myrouter
We lose connectivity on all external subnets, because the router logical port is lost
User should be able to set subnets after creating and attaching external networks to router
See launchpad for more details on what the sequence of events cause this.
Not worth fixing in OSP 14, since that is EOL