1.问题目录表：
1. Bad connection to FS. command aborted. exception: Call to localhost/127.0.0.1:88
2. 88 failed on connection exception: java.net.ConnectException: Connection refused
3. : no further information
错误提示“Bad connection to FS. command aborted. exception: Call tolocalhost/127.0.0.1:88
88failed 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）：
1. $ ./hadoop namenode -format
成功之后重启hadoop就可以了
2如果错误还存在，那么手动删除文件
1. $ bin/hadoop fs -ls /
2. 11/08/18 17:02:35 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
3. .1:9000. Already tried 0 time(s).
4. 11/08/18 17:02:37 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
5. .1:9000. Already tried 1 time(s).
6. 11/08/18 17:02:39 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
7. .1:9000. Already tried 2 time(s).
8. 11/08/18 17:02:41 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
9. .1:9000. Already tried 3 time(s).
10. 11/08/18 17:02:43 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
11. .1:9000. Already tried 4 time(s).
12. 11/08/18 17:02:45 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
13. .1:9000. Already tried 5 time(s).
14. 11/08/18 17:02:46 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
15. .1:9000. Already tried 6 time(s).
16. 11/08/18 17:02:48 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
17. .1:9000. Already tried 7 time(s).
18. 11/08/18 17:02:50 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
19. .1:9000. Already tried 8 time(s).
20. 11/08/18 17:02:52 INFO ipc.Client: Retrying connect to server: localhost/127.0.0
21. .1:9000. Already tried 9 time(s).
1. 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
hadoop格式化失败原因
[root@hadoop home]# hadoop namenode -format
Warning: $HADOOP_HOME is deprecated.
14/01/24 11:41:59 INFO namenode.NameNode: STARTUP_MSG:
/************************************************************
STARTUP_MSG: Starting NameNode
STARTUP_MSG: host = hadoop/192.168.174.174
STARTUP_MSG: args = [-format]
STARTUP_MSG: version = 1.1.2
STARTUP_MSG: build =https://svn.apache.org/repos/asf/hadoop/common/branches/branch-1.1 -r 1440782;compiled by 'hortonfo' on Thu Jan 31 02:03:24 UTC 2013
************************************************************/
Re-format filesystem in /usr/java/hadoop/tmp/dfs/name ? (Y or N) y
Format aborted in /usr/java/hadoop/tmp/dfs/name
14/01/24 11:42:04 INFO namenode.NameNode: SHUTDOWN_MSG:
/************************************************************
SHUTDOWN_MSG: Shutting down NameNode at hadoop/192.168.174.174
************************************************************/
随后启动hadoop,发现http://hdp0:5007无法显示。
将cd/usr/java/hadoop/tmp/dfs文件夹整个删除。然后再格，成功！！！
[root@hadoop dfs]# hadoop namenode -format
Warning: $HADOOP_HOME is deprecated.
14/01/24 11:44:59 INFO namenode.NameNode: STARTUP_MSG:
/************************************************************
STARTUP_MSG: Starting NameNode
STARTUP_MSG: host = hadoop/192.168.174.174
STARTUP_MSG: args = [-format]
STARTUP_MSG: version = 1.1.2
STARTUP_MSG: build = https://svn.apache.org/repos/asf/hadoop/common/branches/branch-1.1-r 1440782; compiled by 'hortonfo' on Thu Jan 31 02:03:24 UTC 2013
************************************************************/
14/01/24 11:44:59 INFO util.GSet: VM type = 32-bit
14/01/24 11:44:59 INFO util.GSet: 2% max memory = 19.33375 MB
14/01/24 11:44:59 INFO util.GSet: capacity = 2^22 = 4194304entries
14/01/24 11:44:59 INFO util.GSet: recommended=4194304, actual=4194304
14/01/24 11:45:00 INFO namenode.FSNamesystem: fsOwner=root
14/01/24 11:45:00 INFO namenode.FSNamesystem: supergroup=supergroup
14/01/24 11:45:00 INFO namenode.FSNamesystem: isPermissionEnabled=false
14/01/24 11:45:00 INFO namenode.FSNamesystem: dfs.block.invalidate.limit=100
14/01/24 11:45:00 INFO namenode.FSNamesystem: isAccessTokenEnabled=falseaccessKeyUpdateInterval=0 min(s), accessTokenLifetime=0 min(s)
14/01/24 11:45:00 INFO namenode.NameNode: Caching file names occuring more than10 times
14/01/24 11:45:00 INFO common.Storage: Image file of size 110 saved in 0seconds.
14/01/24 11:45:00 INFO namenode.FSEditLog: closing edit log: position=4,editlog=/usr/java/hadoop/tmp/dfs/name/current/edits
14/01/24 11:45:00 INFO namenode.FSEditLog: close success: truncate to 4,editlog=/usr/java/hadoop/tmp/dfs/name/current/edits
14/01/24 11:45:01 INFO common.Storage: Storage directory/usr/java/hadoop/tmp/dfs/name has been successfully formatted.
14/01/24 11:45:01 INFO namenode.NameNode: SHUTDOWN_MSG:
/************************************************************
SHUTDOWN_MSG: Shutting down NameNode at hadoop/192.168.174.174
************************************************************//************************************************************
STARTUP_MSG: Starting NameNode
STARTUP_MSG: host = hdp0/192.168.221.100
STARTUP_MSG: args = [-format]
STARTUP_MSG: version = 0.20.2
STARTUP_MSG: build = https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.20 -r911707; compiled
by 'chrisdo' on Fri Feb 19 08:07:34 UTC 2010
************************************************************/
11/04/12 15:33:30 INFO namenode.FSNamesystem:fsOwner=hadoop,hadoop,adm,dialout,cdrom,plugdev,lpadmin,admin,sambashare
11/04/12 15:33:30 INFO namenode.FSNamesystem: supergroup=supergroup
11/04/12 15:33:30 INFO namenode.FSNamesystem: isPermissionEnabled=true
11/04/12 15:33:31 INFO common.Storage: Image file of size 96 saved in 0seconds.
11/04/12 15:33:31 INFO common.Storage: Storage directory /home/hadoop/dfs/namehas been successfully formatted.
11/04/12 15:33:31 INFO namenode.NameNode: SHUTDOWN_MSG:
/************************************************************
SHUTDOWN_MSG: Shutting down NameNode at hdp0/192.168.221.100
************************************************************/