Merge pull request #12319 from mbforbes/nodesNetworkRedux

Implement 'Nodes Network' test for GKE; add optional verbose SSH.

cluster/gke/util.sh

@@ -210,18 +210,17 @@ function get-password() {
     | grep password | cut -f 4 -d ' ')
 }
 
-# Detect the instance name and IP for the master
+# Detect the IP for the master. Note that on GKE, we don't know the name of the
+# master, so KUBE_MASTER is not set.
 #
 # Assumed vars:
 #   ZONE
 #   CLUSTER_NAME
 # Vars set:
-#   KUBE_MASTER
 #   KUBE_MASTER_IP
 function detect-master() {
   echo "... in gke:detect-master()" >&2
   detect-project >&2
-  KUBE_MASTER="k8s-${CLUSTER_NAME}-master"
   KUBE_MASTER_IP=$("${GCLOUD}" "${CMD_GROUP}" container clusters describe \
     --project="${PROJECT}" --zone="${ZONE}" "${CLUSTER_NAME}" \
     | grep endpoint | cut -f 2 -d ' ')