开发者学堂课程【大数据实时计算框架 Spark 快速入门：Standalone+ZooKeeper高可用部署_4】学习笔记，与课程紧密联系，让用户快速学习知识。
课程地址：https://developer.aliyun.com/learning/course/100/detail/1658
Standalone+ZooKeeper 高可用部署_4
配置结果如下：
把配置文件拷贝过去，如下图：
启动 Zookeeper，如下图：
需要停掉再重新启动，如下：
状态为 STANDBY，说明集群就搭建好了，如下图：
Overview
Utilizing Zookeeper to provide leader election and some state storage, you can launch multiple Masters in your cluster connected to the same ZooKeeper instance. One will be elected "leader" and the others will remain in standby mode. If the current leader dies, another Master will be elected, recover the old Master's state, and then resume scheduling. The entire recovery process (from the time the the first leader goes down) should take between 1 and 2 minutes. Note that this delay only affects scheduling new applications - applications that were already running during Master fallover are unaffected.
刷新一下，如下：
启动原来的 Master，结果如下：
跑应用程序 REPL
这里默认创建了 Spark Context，也创建了 sqlContext，如下：
现在可以写 scala 代码：
把 scala 应用程序跑起来，刷新一下，结果如下：
把 Master 停掉，如下：
会有信息报备，如下
并没有真的去执行这个文件，只是标记了一下，如下：
