Hadoop问题：启动hadoop时报namenode未初始化：java.io.IOException: NameNode is not formatted.
1、启动Hadoop
ubuntu@ubuntu:~/hadoop-1.0.4/tmp$ rm -rf *ubuntu@ubuntu:~/hadoop-1.0.4/tmp$ cd ../binubuntu@ubuntu:~/hadoop-1.0.4/bin$ ./stop-all.sh stopping jobtrackerlocalhost: stopping tasktrackerno namenode to stoplocalhost: stopping datanodelocalhost: stopping secondarynamenodeubuntu@ubuntu:~/hadoop-1.0.4/bin$ hadoop namenode -format13/01/24 07:10:45 INFO namenode.NameNode: STARTUP_MSG: /************************************************************STARTUP_MSG: Starting NameNodeSTARTUP_MSG: host = ubuntu/127.0.1.1STARTUP_MSG: args = [-format]STARTUP_MSG: version = 1.0.4STARTUP_MSG: build = https://svn.apache.org/repos/asf/hadoop/common/branches/branch-1.0 -r 1393290; compiled by 'hortonfo' on Wed Oct 3 05:13:58 UTC 2012************************************************************/13/01/24 07:10:46 INFO util.GSet: VM type = 32-bit13/01/24 07:10:46 INFO util.GSet: 2% max memory = 19.33375 MB13/01/24 07:10:46 INFO util.GSet: capacity = 2^22 = 4194304 entries13/01/24 07:10:46 INFO util.GSet: recommended=4194304, actual=419430413/01/24 07:10:46 INFO namenode.FSNamesystem: fsOwner=ubuntu13/01/24 07:10:46 INFO namenode.FSNamesystem: supergroup=supergroup13/01/24 07:10:46 INFO namenode.FSNamesystem: isPermissionEnabled=true13/01/24 07:10:46 INFO namenode.FSNamesystem: dfs.block.invalidate.limit=10013/01/24 07:10:46 INFO namenode.FSNamesystem: isAccessTokenEnabled=false accessKeyUpdateInterval=0 min(s), accessTokenLifetime=0 min(s)13/01/24 07:10:46 INFO namenode.NameNode: Caching file names occuring more than 10 times 13/01/24 07:10:46 INFO common.Storage: Image file of size 112 saved in 0 seconds.13/01/24 07:10:46 INFO common.Storage: Storage directory /home/ubuntu/hadoop-1.0.4/tmp/dfs/name has been successfully formatted.13/01/24 07:10:46 INFO namenode.NameNode: SHUTDOWN_MSG: /************************************************************SHUTDOWN_MSG: Shutting down NameNode at ubuntu/127.0.1.1************************************************************/ubuntu@ubuntu:~/hadoop-1.0.4/bin$ ./start-all.sh starting namenode, logging to /home/ubuntu/hadoop-1.0.4/libexec/../logs/hadoop-ubuntu-namenode-ubuntu.outlocalhost: starting datanode, logging to /home/ubuntu/hadoop-1.0.4/libexec/../logs/hadoop-ubuntu-datanode-ubuntu.outlocalhost: starting secondarynamenode, logging to /home/ubuntu/hadoop-1.0.4/libexec/../logs/hadoop-ubuntu-secondarynamenode-ubuntu.outstarting jobtracker, logging to /home/ubuntu/hadoop-1.0.4/libexec/../logs/hadoop-ubuntu-jobtracker-ubuntu.outlocalhost: starting tasktracker, logging to /home/ubuntu/hadoop-1.0.4/libexec/../logs/hadoop-ubuntu-tasktracker-ubuntu.out
7、原来是修改了配置文件中的tmp目录后没有对hdfs做初始化，导致启动hadoop时报namenode没有初始化的错误。
