..
      Licensed under the Apache License, Version 2.0 (the "License"); you may
      not use this file except in compliance with the License. You may obtain
      a copy of the License at

          http://www.apache.org/licenses/LICENSE-2.0

      Unless required by applicable law or agreed to in writing, software
      distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
      WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
      License for the specific language governing permissions and limitations
      under the License.

Generated using plantuml.

@startuml

title live-migration with ovs-hybrid plug : nova<->neutron interactions

participant nova_conductor
participant nova_compute1
participant nova_compute2
participant neutron_server
participant neutron_l2_agent2
participant neutron_l2_agent1
participant neutron_l3_agent2
participant neutron_l3_agent1

nova_conductor -> nova_compute1 : live_migrate
activate nova_compute1
nova_compute1 -> nova_compute2 : RPC.call : pre_live_migrate()
activate nova_compute2
nova_compute2 -> neutron_server : REST : list_port()
activate neutron_server
neutron_server -> nova_compute2
deactivate neutron_server

group port plugged on host2
    nova_compute2 -> nova_compute2 : plug_vifs()
    activate neutron_l2_agent2
    neutron_l2_agent2 -> neutron_server : RPC.call : get_devices_details_list_and_failed_devices(devices : [port])
    activate neutron_server
    neutron_server -> neutron_l2_agent2
    deactivate neutron_server
    neutron_l2_agent2 -> neutron_server : RPC.call : update_device_list(devices_up : [port])
    activate neutron_server
    neutron_server -> neutron_l2_agent2
    deactivate neutron_server
    note over neutron_server
        port status is never
        changed since port
        is not bound to host2
    end note
    deactivate neutron_l2_agent2
end

nova_compute2 -> nova_compute1
deactivate nova_compute2

group proactive dvr router creation
    nova_compute1 -> neutron_server : REST : update_port('binding:profile'={'migrating_to':'host2'})
    activate neutron_server
    neutron_server -> neutron_l3_agent1: RPC.cast(fanout) : port_update(port)
    activate neutron_l3_agent1
    destroy neutron_l3_agent1
    note over neutron_l3_agent1
        "migrating_to" does
        not match host
    end note
    neutron_server -> neutron_l3_agent2: RPC.cast(fanout) : port_update(port)
    activate neutron_l3_agent2
    note over neutron_l3_agent2
        proactively create DVR router
    end note
    deactivate neutron_l3_agent2
    neutron_server -> nova_compute1
    deactivate neutron_server
end

note over nova_compute1, nova_compute2
    libvirt handles the live-migration
end note
note left of nova_compute1
    live migration
    succeeded
end note

nova_compute1 -> nova_compute1 : post_live_migration
group port unplugged on host1
    nova_compute1 -> nova_compute1 : unplug_vifs()
    activate neutron_l2_agent1
    neutron_l2_agent1 -> neutron_server : RPC.call : update_device_list(devices_down : [port])
    activate neutron_server
    neutron_server -> neutron_server : update_port_status(DOWN)
    neutron_server -> neutron_l2_agent1
    deactivate neutron_l2_agent1
    note over neutron_server
        port status changed to
        DOWN since port is bound
        to host1
    end note
    deactivate neutron_server
end

nova_compute1 -> nova_compute2 : RPC.cast : post_live_migration_at_destination()
deactivate nova_compute1
activate nova_compute2
nova_compute2 -> neutron_server : REST : update_port({'binding:host_id':'host2', 'binding:profile':{}})
activate neutron_server
neutron_server -> neutron_server : update_port_status(DOWN)
neutron_server -> neutron_l2_agent1 : RPC.cast(fanout) : port_update(port)
activate neutron_l2_agent1
destroy neutron_l2_agent1
note over neutron_l2_agent1
    port not hosted
    on host1
end note

neutron_server -> neutron_l2_agent2 : RPC.cast(fanout) : port_update(port)
activate neutron_l2_agent2
neutron_server -> nova_compute2
deactivate nova_compute2
deactivate neutron_server

group port_update processed by agent that really hosts the port
    neutron_l2_agent2 -> neutron_server : RPC.call : get_devices_details_list_and_failed_devices(devices : [port])
    activate neutron_server
    neutron_server -> neutron_server : update_port_status(BUILD)
    neutron_server -> neutron_l2_agent2
    deactivate neutron_server
    neutron_l2_agent2 -> neutron_server : RPC.call : update_device_list(devices_up : [port])
    activate neutron_server
    neutron_server -> neutron_server : update_port_status(ACTIVE)
    neutron_server -> neutron_l2_agent2
    deactivate neutron_server
    note over neutron_server
        port status changed to
        ACTIVE since port
        is now bound to host2
    end note
    deactivate neutron_l2_agent2
end group

@enduml