This is what I am trying to tell that OVN doesn't have any AZ concept because its distributed openflow and there is no such thing DHCP agent. It works with openvswitch plugin but not with OVN plugin. 

We should remove AZ option in network create or make it optional. 



# openstack network agent list
+--------------------------------------+------------------------------+----------+-------------------+-------+-------+----------------------------+
| ID                                   | Agent Type                   | Host     | Availability Zone | Alive | State | Binary                     |
+--------------------------------------+------------------------------+----------+-------------------+-------+-------+----------------------------+
| 734531b5-175a-5bba-8d35-df88ac80754b | OVN Metadata agent           | os-ctrl1 | nova              | :-)   | UP    | neutron-ovn-metadata-agent |
| os-ctrl1                             | OVN Controller Gateway agent | os-ctrl1 | nova              | :-)   | UP    | ovn-controller             |
| ed3f844a-73c6-517e-9108-3c4511869954 | OVN Metadata agent           | os-ctrl2 | nova              | :-)   | UP    | neutron-ovn-metadata-agent |
| os-ctrl2                             | OVN Controller Gateway agent | os-ctrl2 | nova              | :-)   | UP    | ovn-controller             |
| 34bafdf6-05f2-5129-ac0c-bfffce60ee36 | OVN Metadata agent           | os-comp4 |                   | :-)   | UP    | neutron-ovn-metadata-agent |
| os-comp4                             | OVN Controller agent         | os-comp4 |                   | :-)   | UP    | ovn-controller             |
| ba44ee41-4d31-5d28-9d65-961d0399ee90 | OVN Metadata agent           | os-comp5 |                   | :-)   | UP    | neutron-ovn-metadata-agent |
| os-comp5                             | OVN Controller agent         | os-comp5 |                   | :-)   | UP    | ovn-controller             |
| b5a95522-13ee-59d5-b093-8aab843f9efe | OVN Metadata agent           | os-comp2 |                   | :-)   | UP    | neutron-ovn-metadata-agent |
| os-comp2                             | OVN Controller agent         | os-comp2 |                   | :-)   | UP    | ovn-controller             |
| afa98165-a0ad-5f74-abc2-f46048fa5ec2 | OVN Metadata agent           | os-comp1 |                   | :-)   | UP    | neutron-ovn-metadata-agent |
| os-comp1                             | OVN Controller agent         | os-comp1 |                   | :-)   | UP    | ovn-controller             |
| c36ba86c-1742-5b08-842e-fe805e3df3e4 | OVN Metadata agent           | os-ctrl3 | nova              | :-)   | UP    | neutron-ovn-metadata-agent |
| os-ctrl3                             | OVN Controller Gateway agent | os-ctrl3 | nova              | :-)   | UP    | ovn-controller             |
| 3b8100d3-0671-5953-b2e3-c8639dea6006 | OVN Metadata agent           | os-comp3 |                   | :-)   | UP    | neutron-ovn-metadata-agent |
| os-comp3                             | OVN Controller agent         | os-comp3 |                   | :-)   | UP    | ovn-controller             |
+--------------------------------------+------------------------------+----------+-------------------+-------+-------+----------------------------+