def _initialize_summary_output(ns_list):
    """
    Function takes list of namespace names.
    Returns dictionary with summary fields set.
    """

    summary_dict = {}
    summary_dict["CLUSTER"] = {}

    summary_dict["CLUSTER"]["server_version"] = []
    summary_dict["CLUSTER"]["os_version"] = []
    summary_dict["CLUSTER"]["active_features"] = []
    summary_dict["CLUSTER"]["migrations_in_progress"] = False

    summary_dict["CLUSTER"]["device"] = {}
    summary_dict["CLUSTER"]["device"]["count"] = 0
    summary_dict["CLUSTER"]["device"]["count_per_node"] = 0
    summary_dict["CLUSTER"]["device"]["count_same_across_nodes"] = True
    summary_dict["CLUSTER"]["device"]["total"] = 0
    summary_dict["CLUSTER"]["device"]["used"] = 0
    summary_dict["CLUSTER"]["device"]["aval"] = 0
    summary_dict["CLUSTER"]["device"]["used_pct"] = 0
    summary_dict["CLUSTER"]["device"]["aval_pct"] = 0

    summary_dict["CLUSTER"]["memory"] = {}
    summary_dict["CLUSTER"]["memory"]["total"] = 0
    summary_dict["CLUSTER"]["memory"]["aval"] = 0
    summary_dict["CLUSTER"]["memory"]["aval_pct"] = 0

    summary_dict["CLUSTER"]["active_ns"] = 0
    summary_dict["CLUSTER"]["ns_count"] = 0

    summary_dict["CLUSTER"]["license_data"] = {}
    summary_dict["CLUSTER"]["license_data"]["memory_size"] = 0
    summary_dict["CLUSTER"]["license_data"]["device_size"] = 0

    summary_dict["FEATURES"] = {}
    summary_dict["FEATURES"]["NAMESPACE"] = {}

    for ns in ns_list:
        summary_dict["FEATURES"]["NAMESPACE"][ns] = {}

        summary_dict["FEATURES"]["NAMESPACE"][ns]["devices_total"] = 0
        summary_dict["FEATURES"]["NAMESPACE"][ns]["devices_per_node"] = 0
        summary_dict["FEATURES"]["NAMESPACE"][ns]["devices_count_same_across_nodes"] = True

        summary_dict["FEATURES"]["NAMESPACE"][ns]["memory_total"] = 0
        summary_dict["FEATURES"]["NAMESPACE"][ns]["memory_aval"] = 0
        summary_dict["FEATURES"]["NAMESPACE"][ns]["memory_available_pct"] = 0

        summary_dict["FEATURES"]["NAMESPACE"][ns]["disk_total"] = 0
        summary_dict["FEATURES"]["NAMESPACE"][ns]["disk_used"] = 0
        summary_dict["FEATURES"]["NAMESPACE"][ns]["disk_aval"] = 0
        summary_dict["FEATURES"]["NAMESPACE"][ns]["disk_used_pct"] = 0
        summary_dict["FEATURES"]["NAMESPACE"][ns]["disk_available_pct"] = 0

        summary_dict["FEATURES"]["NAMESPACE"][ns]["repl_factor"] = 0
        summary_dict["FEATURES"]["NAMESPACE"][ns]["master_objects"] = 0

        summary_dict["FEATURES"]["NAMESPACE"][ns]["license_data"] = {}

        summary_dict["FEATURES"]["NAMESPACE"][ns]["migrations_in_progress"] = False

    return summary_dict