windows下跑伪分布hadoop，问题小记

yuandan

　　问题目录表：
　　1，Bad connection to FS. command aborted. exception: Call to localhost/127.0.0.1:8888
　　failed on connection exception: java.net.ConnectException: Connection refused



　　2，Bad connection to FS. command aborted.
　　3，在cygwin上执行wordcount时报FileNotFoundException
　　1， windows下，在安装完cygwin，并配置好hadoop参数，到hadoop的bin目录下执行以下代码，

$ ./hadoop fs -ls /
　　遇到错误：

11/08/18 14:56:37 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
.1:8888. Already tried 0 time(s).
11/08/18 14:56:39 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
.1:8888. Already tried 1 time(s).
11/08/18 14:56:41 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
.1:8888. Already tried 2 time(s).
11/08/18 14:56:43 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
.1:8888. Already tried 3 time(s).
11/08/18 14:56:45 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
.1:8888. Already tried 4 time(s).
11/08/18 14:56:47 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
.1:8888. Already tried 5 time(s).
11/08/18 14:56:49 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
.1:8888. Already tried 6 time(s).
11/08/18 14:56:51 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
.1:8888. Already tried 7 time(s).
11/08/18 14:56:53 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
.1:8888. Already tried 8 time(s).
11/08/18 14:56:55 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
.1:8888. Already tried 9 time(s).
Bad connection to FS. command aborted. exception: Call to localhost/127.0.0.1:88
88 failed on connection exception: java.net.ConnectException: Connection refused
: no further information


　　错误提示“Bad connection to FS. command aborted. exception: Call to localhost/127.0.0.1:88
　　88 failed on connection exception: java.net.ConnectException: Connection refused
　　: no further information”
　　起初怀疑是fs服务没有启动，但反复关闭启动多次后仍没用，请教高手后，被建议重新格式化namenode，就可以了。
　　格式化指令如下（在hadoop的bin目录下）：

$ ./hadoop namenode -format
　　成功 之后重启hadoop就可以了
　　2，如果显示的像一下错误信息：

$ bin/hadoop fs -ls /
11/08/18 17:02:35 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
.1:9000. Already tried 0 time(s).
11/08/18 17:02:37 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
.1:9000. Already tried 1 time(s).
11/08/18 17:02:39 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
.1:9000. Already tried 2 time(s).
11/08/18 17:02:41 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
.1:9000. Already tried 3 time(s).
11/08/18 17:02:43 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
.1:9000. Already tried 4 time(s).
11/08/18 17:02:45 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
.1:9000. Already tried 5 time(s).
11/08/18 17:02:46 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
.1:9000. Already tried 6 time(s).
11/08/18 17:02:48 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
.1:9000. Already tried 7 time(s).
11/08/18 17:02:50 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
.1:9000. Already tried 8 time(s).
11/08/18 17:02:52 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
.1:9000. Already tried 9 time(s).
Bad connection to FS. command aborted.
　　错误提示“Bad connection to FS. command aborted.”
　　把你DataNode上的DFS数据全删了，再重新格式化NameNode。
　　即：先将你D盘下tmp目录下所有文件删了，在重复上面第一点的过程
　　3,在cygwin上执行wordcount时报FileNotFoundException
　　原因： tmp路径有问题。配置文件mapred-site.xml中mapred.child.tmp默认是"./tmp"，在windows里会出问题
　　解决：将其改为D:/tmp（这个是windows下默认的，听说改成其他绝对路径也可以，会自动创建），之后重启hadoop即可