On 4/9/2018 9:57 PM, Chen CH Ji wrote: > Could you please help to share whether this kind of event is sent by > neutron-server or neutron agent ? I searched neutron code > from [1][2] this means the agent itself need tell neutron server the > device(VIF) is up then neutron server will send notification > to nova through REST API and in turn consumed by compute node? > > [1]https://github.com/openstack/neutron/tree/master/neutron/notify_port_active_direct > [2]https://github.com/openstack/neutron/blob/master/neutron/plugins/ml2/rpc.py#L264 I believe the neutron agent is the one that is getting (or polling) the information from the underlying network backend when VIFs are plugged or unplugged from a host, then route that information via RPC to the neutron server which then sends an os-server-external-events request to the compute REST API, which then routes the event information down to the nova-compute host where the instance is currently running. -- Thanks, Matt