Hadoop出现namenode running as process 18472. Stop it first.等等，类似的出现了好几个。
namenode running as process 32972. Stop it first. 127.0.0.1: ssh: connect to host 127.0.0.1 port 22: No error 127.0.0.1: ssh: connect to host 127.0.0.1 port 22: No error jobtracker running as process 81312. Stop it first. 127.0.0.1: ssh: connect to host 127.0.0.1 port 22: No error
解决办法：说明你没有启动起来，所以在启动之前你需要 在重新启动hadoop之前要先stop掉所有的hadoop服务。 然后恢复正常启动。
