nova/doc/api_samples/os-multiple-create/multiple-create-post-req.json

{
    "server": {
        "name": "new-server-test",
        "imageRef": "70a599e0-31e7-49b7-b260-868f441e862b",
        "flavorRef": "1",
        "metadata": {
            "My Server Name": "Apache1"
        },
        "return_reservation_id": "True",
        "min_count": "2",
        "max_count": "3"
    }
}