细数搭建hadoop集群中遇到的坑及解决办法

本人环境 centos7，JDK1.8,Hadoop2.8.2node 测试环境时报错1.WARN hdfs.DFSClient:DataStreamer Exception.There are 0 datanode(s) running and no node(s) areexcluded in this operation.linux 缘由及解决办法：Linux默认关闭防火墙（不敢彻底肯定，但

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