Comment 2 for bug 1913312

What version of Juju are you running here?

When you add the devices via lxc config, are you sure that those NICs are operational on the machines?

Perhaps a "netplan apply" or some such is necessary to bring the NICs "up". This would cause the machine agent in the container to report the NIC and associate it with the correct space via its subnet.

If you check via `juju show machine {ID} --format yaml` you will see the NIC if it is being reported properly to Juju.