os-net-config/etc/os-net-config/samples/ib_child_interface.json

{
  "network_config": [
    {
      "type": "ib_interface",
      "name": "ib0",
      "use_dhcp": false
    },
    {
      "type": "ib_child_interface",
      "parent": "ib0",
      "pkey_id": 100,
      "use_dhcp": false,
      "addresses": [
        {
          "ip_netmask": "10.20.30.40/24"
        }
      ]
    }
  ]
}