Add MAX_PODS_PER_NODE env allowing kubelet to be max-pods aware.

cluster/gce/config-default.sh

@@ -305,6 +305,8 @@ if [ ${ENABLE_IP_ALIASES} = true ]; then
   PROVIDER_VARS="${PROVIDER_VARS:-} ENABLE_IP_ALIASES"
   PROVIDER_VARS="${PROVIDER_VARS:-} NODE_IPAM_MODE"
   PROVIDER_VARS="${PROVIDER_VARS:-} SECONDARY_RANGE_NAME"
+  # Number of Pods that can run on this node.
+  MAX_PODS_PER_NODE=${MAX_PODS_PER_NODE:-110}
 fi
 
 # Enable GCE Alpha features.

cluster/gce/config-test.sh

@@ -312,6 +312,8 @@ if [ ${ENABLE_IP_ALIASES} = true ]; then
   PROVIDER_VARS="${PROVIDER_VARS:-} ENABLE_IP_ALIASES"
   PROVIDER_VARS="${PROVIDER_VARS:-} NODE_IPAM_MODE"
   PROVIDER_VARS="${PROVIDER_VARS:-} SECONDARY_RANGE_NAME"
+  # Number of Pods that can run on this node.
+  MAX_PODS_PER_NODE=${MAX_PODS_PER_NODE:-110}
 fi
 
 # Enable GCE Alpha features.

cluster/gce/util.sh

@@ -677,6 +677,9 @@ function construct-kubelet-flags {
   if [[ -n "${CONTAINER_RUNTIME_ENDPOINT:-}" ]]; then
     flags+=" --container-runtime-endpoint=${CONTAINER_RUNTIME_ENDPOINT}"
   fi
+  if [[ -n "${MAX_PODS_PER_NODE:-}" ]]; then
+    flags+=" --max-pods=${MAX_PODS_PER_NODE}"
+  fi
 
   KUBELET_ARGS="${flags}"
 }
@@ -1138,6 +1141,11 @@ EOF
 SCHEDULING_ALGORITHM_PROVIDER: $(yaml-quote ${SCHEDULING_ALGORITHM_PROVIDER})
 EOF
   fi
+  if [ -n "${MAX_PODS_PER_NODE:-}" ]; then
+    cat >>$file <<EOF
+MAX_PODS_PER_NODE: $(yaml-quote ${MAX_PODS_PER_NODE})
+EOF
+  fi
 }
 
 function sha1sum-file() {