Determine address of master so that workers
    can connect to it. If the environment variable
    SPARK_LOCAL_IP is set, that address will be used.

    :param port: port on which the application runs
    :return: Master address

    Example usage:
        SPARK_LOCAL_IP=127.0.0.1 spark-submit --master \
            local[8] examples/mllib_mlp.py

def determine_master(port=4000):
    """Determine address of master so that workers
    can connect to it. If the environment variable
    SPARK_LOCAL_IP is set, that address will be used.

    :param port: port on which the application runs
    :return: Master address

    Example usage:
        SPARK_LOCAL_IP=127.0.0.1 spark-submit --master \
            local[8] examples/mllib_mlp.py
    """
    if os.environ.get('SPARK_LOCAL_IP'):
        return os.environ['SPARK_LOCAL_IP'] + ":" + str(port)
    else:
        return gethostbyname(gethostname()) + ":" + str(port)