function load_cluster_topology() {
  CLUSTER_TOPOLOGY_CONFIG_FILE="${1}"

  if [[ ! -f "${CLUSTER_TOPOLOGY_CONFIG_FILE}" ]]; then
    log 'cluster topology configuration file is not specified'
    exit 1
  fi

  export CLUSTER_NAMES
  export CLUSTER_POD_SUBNETS
  export CLUSTER_SVC_SUBNETS
  export CLUSTER_NETWORK_ID

# without testing properly.
#
# This function will properly handle any type of path including those with spaces using the
# loading pattern specified by *kubectl config*.
#
# testcase: "a:b c:d"
# testcase: "a b:c d:e f"
# testcase: "a b:c:d e"
parse_KUBECONFIG () {
TMPDIR=""
if [[ "$1" =~ ([^:]*):(.*) ]]; then
  while true; do