Add comments and change function name

cluster/gce/gci/configure-helper.sh

@@ -182,11 +182,11 @@ function mount-master-pd {
   chgrp -R etcd "${mount_point}/var/etcd"
 }
 
-# replace_prefixed_line ensures:
+# append_or_replace_prefixed_line ensures:
 # 1. the specified file exists
 # 2. existing lines with the specified ${prefix} are removed
 # 3. a new line with the specified ${prefix}${suffix} is appended
-function replace_prefixed_line {
+function append_or_replace_prefixed_line {
   local -r file="${1:-}"
   local -r prefix="${2:-}"
   local -r suffix="${3:-}"
@@ -286,29 +286,30 @@ function create-master-auth {
   local -r auth_dir="/etc/srv/kubernetes"
   local -r basic_auth_csv="${auth_dir}/basic_auth.csv"
   if [[ -n "${KUBE_PASSWORD:-}" && -n "${KUBE_USER:-}" ]]; then
+    # Remove basic_auth_csv because we will rewrite it.
     if [[ -e "${basic_auth_csv}" && "${METADATA_CLOBBERS_CONFIG:-false}" == "true" ]]; then
       rm "${basic_auth_csv}"
     fi
-    replace_prefixed_line "${basic_auth_csv}" "${KUBE_PASSWORD},${KUBE_USER}," "admin,system:masters"
+    append_or_replace_prefixed_line "${basic_auth_csv}" "${KUBE_PASSWORD},${KUBE_USER},"      "admin,system:masters"
   fi
   local -r known_tokens_csv="${auth_dir}/known_tokens.csv"
   if [[ -n "${KUBE_BEARER_TOKEN:-}" ]]; then
-    replace_prefixed_line "${known_tokens_csv}" "${KUBE_BEARER_TOKEN},"             "admin,admin,system:masters"
+    append_or_replace_prefixed_line "${known_tokens_csv}" "${KUBE_BEARER_TOKEN},"             "admin,admin,system:masters"
   fi
   if [[ -n "${KUBE_CONTROLLER_MANAGER_TOKEN:-}" ]]; then
-    replace_prefixed_line "${known_tokens_csv}" "${KUBE_CONTROLLER_MANAGER_TOKEN}," "system:kube-controller-manager,uid:system:kube-controller-manager"
+    append_or_replace_prefixed_line "${known_tokens_csv}" "${KUBE_CONTROLLER_MANAGER_TOKEN}," "system:kube-controller-manager,uid:system:kube-controller-manager"
   fi
   if [[ -n "${KUBE_SCHEDULER_TOKEN:-}" ]]; then
-    replace_prefixed_line "${known_tokens_csv}" "${KUBE_SCHEDULER_TOKEN},"          "system:kube-scheduler,uid:system:kube-scheduler"
+    append_or_replace_prefixed_line "${known_tokens_csv}" "${KUBE_SCHEDULER_TOKEN},"          "system:kube-scheduler,uid:system:kube-scheduler"
   fi
   if [[ -n "${KUBELET_TOKEN:-}" ]]; then
-    replace_prefixed_line "${known_tokens_csv}" "${KUBELET_TOKEN},"                 "kubelet,uid:kubelet,system:nodes"
+    append_or_replace_prefixed_line "${known_tokens_csv}" "${KUBELET_TOKEN},"                 "kubelet,uid:kubelet,system:nodes"
   fi
   if [[ -n "${KUBE_PROXY_TOKEN:-}" ]]; then
-    replace_prefixed_line "${known_tokens_csv}" "${KUBE_PROXY_TOKEN},"              "system:kube-proxy,uid:kube_proxy"
+    append_or_replace_prefixed_line "${known_tokens_csv}" "${KUBE_PROXY_TOKEN},"              "system:kube-proxy,uid:kube_proxy"
   fi
   if [[ -n "${NODE_PROBLEM_DETECTOR_TOKEN:-}" ]]; then
-    replace_prefixed_line "${known_tokens_csv}" "${NODE_PROBLEM_DETECTOR_TOKEN},"   "system:node-problem-detector,uid:node-problem-detector"
+    append_or_replace_prefixed_line "${known_tokens_csv}" "${NODE_PROBLEM_DETECTOR_TOKEN},"   "system:node-problem-detector,uid:node-problem-detector"
   fi
   local use_cloud_config="false"
   cat <<EOF >/etc/gce.conf