环境: spark 1.6, ElasticSearch 1.6.1, elasticsearch-hadoop
通过 elasticsearch-hadoop可以将spark 处理后的数据保存在Elastic上，后续数据的检查和查询非常方便。
https://db-blog.web.cern.ch/blog/prasanth-kothuri/2016-05-integrating-hadoop-and-elasticsearch-%E2%80%93-part-2-%E2%80%93-writing-and-querying
https://www.elastic.co/guide/en/elasticsearch/hadoop/master/spark.html
https://spark-packages.org/package/elastic/elasticsearch-hadoop
