Comment 13 for bug 1851248

Please provide more wider output, because this role is included a lot of times and used throughout the project.
My guess would be that it's failing during this include https://opendev.org/openstack/openstack-ansible/src/branch/master/tests/roles/bootstrap-host/tasks/prepare_networking.yml#L183

And I can imagine this happening in case smth is weird with the host networking where you're trying to run AIO. For example, ansible_default_ipv4.interface is not defined and https://opendev.org/openstack/openstack-ansible/src/branch/master/tests/roles/bootstrap-host/defaults/main.yml#L108 may cause this error then.

You can try setting bootstrap_host_public_interface variable in user_variables.yml to the interface name you're using as a public interface.

I just tested this with clean ubuntu 20.04 VM and haven't faced any issues:
TASK [systemd_service : Create TEMP run dir] **********************************************************************************************************************************************************************************************************************************
changed: [localhost] => (item={'service_name': 'networking-post-up', 'config_overrides': {'Unit': {'Description': 'networking-post-up', 'After': 'network-online.target', 'Wants': 'network-online.target'}, 'Service': {'RemainAfterExit': True}}, 'service_type': 'oneshot', 'execstarts': ['-/sbin/iptables -t nat -A POSTROUTING -o ens3 -j MASQUERADE', '-/sbin/ethtool -K br-mgmt gso off sg off tso off tx off', '-/sbin/ethtool -K br-vxlan gso off sg off tso off tx off', '-/sbin/ethtool -K br-storage gso off sg off tso off tx off', '-/sbin/ethtool -K br-vlan gso off sg off tso off tx off', '-/sbin/ethtool -K br-dbaas gso off sg off tso off tx off', '-/sbin/ethtool -K br-lbaas gso off sg off tso off tx off', '-/sbin/ip link set eth12 up', '-/sbin/ip link set br-vlan-veth up', '-/sbin/ethtool -K eth12 gso off sg off tso off tx off', '-/sbin/ip link set eth13 up', '-/sbin/ip link set br-dbaas-veth up', '-/sbin/ethtool -K eth13 gso off sg off tso off tx off', '-/sbin/ip link set eth14 up', '-/sbin/ip link set br-lbaas-veth up', '-/sbin/ethtool -K eth14 gso off sg off tso off tx off'], 'execstops': ['/sbin/iptables -t nat -D POSTROUTING -o ens3 -j MASQUERADE'], 'enabled': True, 'state': 'started'})