1. Sorry, my bad, was copying you from my phone, so the extra section (container_skel) that is required has slipped my paste. So /etc/openstack_deploy/env.d/nova.yml should look like this:

2. Now I actually see more issues in defined openstack_user_config. I'm not sure if that is the reason of the error or not, but it still must be adjusted:

a) replace network_hosts with network-infra_hosts. Defining network_hosts also adds infra servers to neutron_l3_agent (and other agents) which has in fact no effect, but triggers a bug, where run_once is treated wrongly. But this will cause failure down the line and I assume that's not it yet. You might need to clean up inventory as a result.

b) also define network-northd_hosts - this usually is usually set to infra nodes, and spawns inside LXC. I would also suggest to check out doc on OVN configuration: https://docs.openstack.org/openstack-ansible-os_neutron/latest/app-ovn.html

c) For the issue itself. Most likely, it is looking for `container_bridge` or `host_bind_override` key for some network. As one of these keys are expected in order to create a mapping and ovs bridges for you. It does combine net_name and one of these keys. So it would be interesting to see adjusted openstack_user_config once the above issues are sorted out.

I can also suggest defining mappings in neutron_provider_networks directly, like mentioned in the documentation above.