func (data UserDataMap) ToUserData() ([]byte, error) {
	return json.MarshalIndent(data, "", "\t")
}
Converts a UserDataMap to JSON-string
package nodes
import (
	"encoding/base64"
	"encoding/json"
	"io/ioutil"
	"os"
	"path/filepath"
)
type ConfigDrive struct {
	UserData       UserDataBuilder        `json:"user_data"`
	MetaData       map[string]interface{} `json:"meta_data"`
	NetworkData    map[string]interface{} `json:"network_data"`
	Version        string                 `json:"-"`
	BuildDirectory string                 `json:"-"`
}
type UserDataBuilder interface {
	ToUserData() ([]byte, error)
}
type UserDataMap map[string]interface{}
type UserDataString string