os-net-config/etc/os-net-config/samples/bridge_dhcp.yaml

network_config:
  -
    type: ovs_bridge
    name: br-ctlplane
    use_dhcp: true
    ovs_extra:
      - br-set-external-id br-ctlplane bridge-id br-ctlplane
    members:
      -
        type: interface
        name: em1