nova/doc/v3/api_samples/os-disk-config/server-post-req.json

{
    "server" : {
        "name" : "new-server-test",
        "imageRef" : "http://openstack.example.com/openstack/images/70a599e0-31e7-49b7-b260-868f441e862b",
        "flavorRef" : "http://openstack.example.com/openstack/flavors/1",
        "metadata" : {
            "My Server Name" : "Apache1"
        }
    }
}