Hadoop問題：啓動hadoop時報namenode未初始化：java.io.IOException: NameNode is not formatted.
1、啓動Hadoop
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.out localhost: starting datanode, logging to /home/ubuntu/hadoop-1.0.4/libexec/../logs/hadoop-ubuntu-datanode-ubuntu.out localhost: starting secondarynamenode, logging to /home/ubuntu/hadoop-1.0.4/libexec/../logs/hadoop-ubuntu-secondarynamenode-ubuntu.out starting jobtracker, logging to /home/ubuntu/hadoop-1.0.4/libexec/../logs/hadoop-ubuntu-jobtracker-ubuntu.out localhost: starting tasktracker, logging to /home/ubuntu/hadoop-1.0.4/libexec/../logs/hadoop-ubuntu-tasktracker-ubuntu.out
2、訪問localhost:50070失敗，說明namenode啓動失敗
3、查看namenode啓動日誌
ubuntu@ubuntu:~/hadoop-1.0.4/bin$ cd ../logs ubuntu@ubuntu:~/hadoop-1.0.4/logs$ view hadoop-ubuntu-namenode-ubuntu.log /************************************************************ STARTUP_MSG: Starting NameNode STARTUP_MSG: host = ubuntu/127.0.1.1 STARTUP_MSG: args = [] STARTUP_MSG: version = 1.0.4 STARTUP_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 ************************************************************/ 2013-01-24 07:05:46,936 INFO org.apache.hadoop.metrics2.impl.MetricsConfig: loaded properties from hadoop-metrics2.properties 2013-01-24 07:05:46,945 INFO org.apache.hadoop.metrics2.impl.MetricsSourceAdapter: MBean for source MetricsSystem,sub=Stats registered. 2013-01-24 07:05:46,945 INFO org.apache.hadoop.metrics2.impl.MetricsSystemImpl: Scheduled snapshot period at 10 second(s). 2013-01-24 07:05:46,945 INFO org.apache.hadoop.metrics2.impl.MetricsSystemImpl: NameNode metrics system started 2013-01-24 07:05:47,053 INFO org.apache.hadoop.metrics2.impl.MetricsSourceAdapter: MBean for source ugi registered. 2013-01-24 07:05:47,058 WARN org.apache.hadoop.metrics2.impl.MetricsSystemImpl: Source name ugi already exists! 2013-01-24 07:05:47,064 INFO org.apache.hadoop.metrics2.impl.MetricsSourceAdapter: MBean for source jvm registered. 2013-01-24 07:05:47,064 INFO org.apache.hadoop.metrics2.impl.MetricsSourceAdapter: MBean for source NameNode registered. 2013-01-24 07:05:47,092 INFO org.apache.hadoop.hdfs.util.GSet: VM type = 32-bit 2013-01-24 07:05:47,092 INFO org.apache.hadoop.hdfs.util.GSet: 2% max memory = 19.33375 MB 2013-01-24 07:05:47,092 INFO org.apache.hadoop.hdfs.util.GSet: capacity = 2^22 = 4194304 entries 2013-01-24 07:05:47,092 INFO org.apache.hadoop.hdfs.util.GSet: recommended=4194304, actual=4194304 2013-01-24 07:05:47,140 INFO org.apache.hadoop.hdfs.server.namenode.FSNamesystem: fsOwner=ubuntu 2013-01-24 07:05:47,140 INFO org.apache.hadoop.hdfs.server.namenode.FSNamesystem: supergroup=supergroup 2013-01-24 07:05:47,140 INFO org.apache.hadoop.hdfs.server.namenode.FSNamesystem: isPermissionEnabled=true 2013-01-24 07:05:47,143 INFO org.apache.hadoop.hdfs.server.namenode.FSNamesystem: dfs.block.invalidate.limit=100 2013-01-24 07:05:47,143 INFO org.apache.hadoop.hdfs.server.namenode.FSNamesystem: isAccessTokenEnabled=false accessKeyUpdateInterval=0 min(s), accessTokenLifetime=0 min(s) 2013-01-24 07:05:47,154 INFO org.apache.hadoop.hdfs.server.namenode.FSNamesystem: Registered FSNamesystemStateMBean and NameNodeMXBean 2013-01-24 07:05:47,169 INFO org.apache.hadoop.hdfs.server.namenode.NameNode: Caching file names occuring more than 10 times 2013-01-24 07:05:47,174 ERROR org.apache.hadoop.hdfs.server.namenode.FSNamesystem: FSNamesystem initialization failed. java.io.IOException: NameNode is not formatted. at org.apache.hadoop.hdfs.server.namenode.FSImage.recoverTransitionRead(FSImage.java:330) at org.apache.hadoop.hdfs.server.namenode.FSDirectory.loadFSImage(FSDirectory.java:100) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.initialize(FSNamesystem.java:388) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.<init>(FSNamesystem.java:362) at org.apache.hadoop.hdfs.server.namenode.NameNode.initialize(NameNode.java:276) at org.apache.hadoop.hdfs.server.namenode.NameNode.<init>(NameNode.java:496) at org.apache.hadoop.hdfs.server.namenode.NameNode.createNameNode(NameNode.java:1279) at org.apache.hadoop.hdfs.server.namenode.NameNode.main(NameNode.java:1288) 2013-01-24 07:05:47,175 ERROR org.apache.hadoop.hdfs.server.namenode.NameNode: java.io.IOException: NameNode is not formatted. at org.apache.hadoop.hdfs.server.namenode.FSImage.recoverTransitionRead(FSImage.java:330) at org.apache.hadoop.hdfs.server.namenode.FSDirectory.loadFSImage(FSDirectory.java:100) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.initialize(FSNamesystem.java:388) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.<init>(FSNamesystem.java:362) at org.apache.hadoop.hdfs.server.namenode.NameNode.initialize(NameNode.java:276) at org.apache.hadoop.hdfs.server.namenode.NameNode.<init>(NameNode.java:496) at org.apache.hadoop.hdfs.server.namenode.NameNode.createNameNode(NameNode.java:1279) at org.apache.hadoop.hdfs.server.namenode.NameNode.main(NameNode.java:1288)
其中"2013-01-24 07:05:47,174 ERROR org.apache.hadoop.hdfs.server.namenode.FSNamesystem: FSNamesystem initialization failed.
java.io.IOException: NameNode is not formatted."一行顯示，namenode未初始化。
4、初始化namenode，卻提示是否重新初始化namenode，於是輸入Y。
ubuntu@ubuntu:~/hadoop-1.0.4$ bin/hadoop namenode -format 13/01/24 07:05:08 INFO namenode.NameNode: STARTUP_MSG: /************************************************************ STARTUP_MSG: Starting NameNode STARTUP_MSG: host = ubuntu/127.0.1.1 STARTUP_MSG: args = [-format] STARTUP_MSG: version = 1.0.4 STARTUP_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 ************************************************************/ Re-format filesystem in /home/ubuntu/hadoop-1.0.4/tmp/dfs/name ? (Y or N) y Format aborted in /home/ubuntu/hadoop-1.0.4/tmp/dfs/name 13/01/24 07:05:12 INFO namenode.NameNode: SHUTDOWN_MSG: /************************************************************ SHUTDOWN_MSG: Shutting down NameNode at ubuntu/127.0.1.1 ************************************************************/
5、初始化後，重新啓動hadoop，localhost:50070仍然訪問失敗。查看namenode啓動日誌，依然報namenode沒有初始化的錯誤。
6、於是刪除core-site.xml配置文件中配置的tmp目錄下的所有文件；
將hadoop所有服務停止；
再次啓動hadoop，訪問localhost:50070成功。
ubuntu@ubuntu:~/hadoop-1.0.4/tmp$ rm -rf * ubuntu@ubuntu:~/hadoop-1.0.4/tmp$ cd ../bin ubuntu@ubuntu:~/hadoop-1.0.4/bin$ ./stop-all.sh stopping jobtracker localhost: stopping tasktracker no namenode to stop localhost: stopping datanode localhost: stopping secondarynamenode ubuntu@ubuntu:~/hadoop-1.0.4/bin$ hadoop namenode -format 13/01/24 07:10:45 INFO namenode.NameNode: STARTUP_MSG: /************************************************************ STARTUP_MSG: Starting NameNode STARTUP_MSG: host = ubuntu/127.0.1.1 STARTUP_MSG: args = [-format] STARTUP_MSG: version = 1.0.4 STARTUP_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-bit 13/01/24 07:10:46 INFO util.GSet: 2% max memory = 19.33375 MB 13/01/24 07:10:46 INFO util.GSet: capacity = 2^22 = 4194304 entries 13/01/24 07:10:46 INFO util.GSet: recommended=4194304, actual=4194304 13/01/24 07:10:46 INFO namenode.FSNamesystem: fsOwner=ubuntu 13/01/24 07:10:46 INFO namenode.FSNamesystem: supergroup=supergroup 13/01/24 07:10:46 INFO namenode.FSNamesystem: isPermissionEnabled=true 13/01/24 07:10:46 INFO namenode.FSNamesystem: dfs.block.invalidate.limit=100 13/01/24 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.out localhost: starting datanode, logging to /home/ubuntu/hadoop-1.0.4/libexec/../logs/hadoop-ubuntu-datanode-ubuntu.out localhost: starting secondarynamenode, logging to /home/ubuntu/hadoop-1.0.4/libexec/../logs/hadoop-ubuntu-secondarynamenode-ubuntu.out starting jobtracker, logging to /home/ubuntu/hadoop-1.0.4/libexec/../logs/hadoop-ubuntu-jobtracker-ubuntu.out localhost: starting tasktracker, logging to /home/ubuntu/hadoop-1.0.4/libexec/../logs/hadoop-ubuntu-tasktracker-ubuntu.out
7、原來是修改了配置文件中的tmp目錄後沒有對hdfs做初始化，導致啓動hadoop時報namenode沒有初始化的錯誤。