Merge the old single-node and multi-node ubuntu deployment into one better approach and update the guidance

cluster/ubuntu/deployAddons.sh

@@ -0,0 +1,32 @@
+#!/bin/bash
+
+# Copyright 2015 The Kubernetes Authors All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# deploy the add-on services after the cluster is available
+
+set -e
+
+KUBE_ROOT=$(dirname "${BASH_SOURCE}")/../..
+source "config-default.sh"
+
+if [ "${ENABLE_CLUSTER_DNS}" == true ]; then
+	echo "Deploying DNS on kubernetes"
+	sed -e "s/{{ pillar\['dns_replicas'\] }}/${DNS_REPLICAS}/g;s/{{ pillar\['dns_domain'\] }}/${DNS_DOMAIN}/g" ../../cluster/addons/dns/skydns-rc.yaml.in > skydns-rc.yaml
+	sed -e "s/{{ pillar\['dns_server'\] }}/${DNS_SERVER_IP}/g" ../../cluster/addons/dns/skydns-svc.yaml.in > skydns-svc.yaml
+	# use kubectl to create skydns rc and service
+	"${KUBE_ROOT}/cluster/kubectl.sh" create -f skydns-rc.yaml
+	"${KUBE_ROOT}/cluster/kubectl.sh" create -f skydns-svc.yaml
+	
+fi