Comment 1 for bug 2019798

So the facility does exist in the neutron-api charm for a subordinate to get a restart over the neutron-plugin-api-subordianates relation using the "restart_trigger" key. However, it doesn't look like the neutron-api-plugin-ovn charm uses the key sadly.

One place to start might be the configure_neutron() function which sets up the data to be sent to the neutron-api principal charm; it would just need to add a 'restart_trigger' using the default str(uuid.uuid4()) assignment to ensure that neutron-api causes a restart.