diff --git a/cluster/gce/config-default.sh b/cluster/gce/config-default.sh
index 0e18a974a8c..c8463f8f2b7 100755
--- a/cluster/gce/config-default.sh
+++ b/cluster/gce/config-default.sh
@@ -201,6 +201,7 @@ if [[ ! -z "${NODE_ACCELERATORS}" ]]; then
 fi
 
 # Optional: Install cluster DNS.
+# Set CLUSTER_DNS_CORE_DNS to 'true' to install CoreDNS instead of kube-dns.
 CLUSTER_DNS_CORE_DNS="${CLUSTER_DNS_CORE_DNS:-false}"
 ENABLE_CLUSTER_DNS="${KUBE_ENABLE_CLUSTER_DNS:-true}"
 DNS_SERVER_IP="${KUBE_DNS_SERVER_IP:-10.0.0.10}"
diff --git a/cluster/gce/config-test.sh b/cluster/gce/config-test.sh
index 3d06fa5cd69..42b9f47856a 100755
--- a/cluster/gce/config-test.sh
+++ b/cluster/gce/config-test.sh
@@ -238,7 +238,8 @@ if [[ ${KUBE_ENABLE_INSECURE_REGISTRY:-false} == "true" ]]; then
 fi
 
 # Optional: Install cluster DNS.
-CLUSTER_DNS_CORE_DNS="${CLUSTER_DNS_CORE_DNS:-true}"
+# Set CLUSTER_DNS_CORE_DNS to 'true' to install CoreDNS instead of kube-dns.
+CLUSTER_DNS_CORE_DNS="${CLUSTER_DNS_CORE_DNS:-false}"
 ENABLE_CLUSTER_DNS="${KUBE_ENABLE_CLUSTER_DNS:-true}"
 DNS_SERVER_IP="10.0.0.10"
 DNS_DOMAIN="cluster.local"