将hadoop的core-site.xml中配置的hadoop.tmp.dir 的目录删除再启动hadoop后，会报错：
INFO ipc.Client: Retrying connect to server: master/192.168.0.45:54310. Already tried 0 time.......
原因是忘记执行hadoop namenode -format，
将hadoop停掉，执行下hadoop namenode -format命令，启动hadoop就OK了
将hadoop的core-site.xml中配置的hadoop.tmp.dir 的目录删除再启动hadoop后，会报错：
INFO ipc.Client: Retrying connect to server: master/192.168.0.45:54310. Already tried 0 time.......
原因是忘记执行hadoop namenode -format，
将hadoop停掉，执行下hadoop namenode -format命令，启动hadoop就OK了