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

cluster/ubuntu/reconfDocker.sh

@@ -0,0 +1,53 @@
+#!/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.
+
+# reconfigure docker network setting
+
+if [ "$(id -u)" != "0" ]; then
+  echo >&2 "Please run as root"
+  exit 1
+fi
+
+source ~/kube/config-default.sh
+
+attempt=0
+while true; do
+  /opt/bin/etcdctl get /coreos.com/network/config 
+  if [[ "$?" == 0 ]]; then
+    break
+  else
+  	# enough timeout?? 
+    if (( attempt > 600 )); then
+      echo "timeout for waiting network config" > ~/kube/err.log
+      exit 2
+    fi
+
+    /opt/bin/etcdctl mk /coreos.com/network/config "{\"Network\":\"${FLANNEL_NET}\"}"
+    attempt=$((attempt+1))
+    sleep 3
+  fi
+done
+
+#wait some secs for /run/flannel/subnet.env ready
+sleep 15
+sudo ip link set dev docker0 down
+sudo brctl delbr docker0
+
+source /run/flannel/subnet.env
+
+echo DOCKER_OPTS=\"-H tcp://127.0.0.1:4243 -H unix:///var/run/docker.sock \
+  --bip=${FLANNEL_SUBNET} --mtu=${FLANNEL_MTU}\" > /etc/default/docker
+sudo service docker restart