注意到以下错误行不？
java.io.FileNotFoundException: /app/hadoop/tmp/dfs/name/current/VERSION (Permission denied)
印象中，刚才用ROOT帐号试着启动了一下。
X，我再换回HDUSER用户就不行了。
进入VERSION目录一看，原来每次启动之后，NAME目录下的属性会变成启动用户ROOT的。
于是更改回HDUSER。
一切OK。
~~~~~~~~~~~~~~~~~~~~~~~
2013-04-11 01:52:51,606 INFO org.apache.hadoop.hdfs.server.namenode.NameNode: STARTUP_MSG:
/************************************************************
STARTUP_MSG: Starting NameNode
STARTUP_MSG: host = Master/192.168.7.238
STARTUP_MSG: args = []
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
************************************************************/
2013-04-11 01:52:53,212 INFO org.apache.hadoop.metrics2.impl.MetricsConfig: loaded properties from hadoop-metrics2.properties
2013-04-11 01:52:53,324 INFO org.apache.hadoop.metrics2.impl.MetricsSourceAdapter: MBean for source MetricsSystem,sub=Stats registered.
2013-04-11 01:52:53,333 INFO org.apache.hadoop.metrics2.impl.MetricsSystemImpl: Scheduled snapshot period at 10 second(s).
2013-04-11 01:52:53,333 INFO org.apache.hadoop.metrics2.impl.MetricsSystemImpl: NameNode metrics system started
2013-04-11 01:52:55,098 INFO org.apache.hadoop.metrics2.impl.MetricsSourceAdapter: MBean for source ugi registered.
2013-04-11 01:52:55,408 INFO org.apache.hadoop.metrics2.impl.MetricsSourceAdapter: MBean for source jvm registered.
2013-04-11 01:52:55,442 INFO org.apache.hadoop.metrics2.impl.MetricsSourceAdapter: MBean for source NameNode registered.
2013-04-11 01:52:55,771 INFO org.apache.hadoop.hdfs.util.GSet: VM type = 64-bit
2013-04-11 01:52:55,772 INFO org.apache.hadoop.hdfs.util.GSet: 2% max memory = 19.33375 MB
2013-04-11 01:52:55,772 INFO org.apache.hadoop.hdfs.util.GSet: capacity = 2^21 = 2097152 entries
2013-04-11 01:52:55,772 INFO org.apache.hadoop.hdfs.util.GSet: recommended=2097152, actual=2097152
2013-04-11 01:52:56,135 INFO org.apache.hadoop.hdfs.server.namenode.FSNamesystem: fsOwner=hduser
2013-04-11 01:52:56,136 INFO org.apache.hadoop.hdfs.server.namenode.FSNamesystem: supergroup=supergroup
2013-04-11 01:52:56,136 INFO org.apache.hadoop.hdfs.server.namenode.FSNamesystem: isPermissionEnabled=true
2013-04-11 01:52:56,219 INFO org.apache.hadoop.hdfs.server.namenode.FSNamesystem: dfs.block.invalidate.limit=100
2013-04-11 01:52:56,220 INFO org.apache.hadoop.hdfs.server.namenode.FSNamesystem: isAccessTokenEnabled=false accessKeyUpdateInterval=0 min(s), accessTokenLifetime=0 min(s)
2013-04-11 01:52:58,978 INFO org.apache.hadoop.hdfs.server.namenode.FSNamesystem: Registered FSNamesystemStateMBean and NameNodeMXBean
2013-04-11 01:52:59,185 INFO org.apache.hadoop.hdfs.server.namenode.NameNode: Caching file names occuring more than 10 times
2013-04-11 01:52:59,351 ERROR org.apache.hadoop.hdfs.server.namenode.FSNamesystem: FSNamesystem initialization failed.
java.io.FileNotFoundException: /app/hadoop/tmp/dfs/name/current/VERSION (Permission denied)
at java.io.RandomAccessFile.open(Native Method)
at java.io.RandomAccessFile.<init>(RandomAccessFile.java:233)
at org.apache.hadoop.hdfs.server.common.Storage$StorageDirectory.read(Storage.java:219)
at org.apache.hadoop.hdfs.server.common.Storage$StorageDirectory.read(Storage.java:215)
at org.apache.hadoop.hdfs.server.namenode.FSImage.recoverTransitionRead(FSImage.java:314)
at org.apache.hadoop.hdfs.server.namenode.FSDirectory.loadFSImage(FSDirectory.java:100)
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.initialize(FSNamesystem.java:411)
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.<init>(FSNamesystem.java:379)
at org.apache.hadoop.hdfs.server.namenode.NameNode.initialize(NameNode.java:284)
at org.apache.hadoop.hdfs.server.namenode.NameNode.<init>(NameNode.java:536)
at org.apache.hadoop.hdfs.server.namenode.NameNode.createNameNode(NameNode.java:1410)
at org.apache.hadoop.hdfs.server.namenode.NameNode.main(NameNode.java:1419)
2013-04-11 01:52:59,418 ERROR org.apache.hadoop.hdfs.server.namenode.NameNode: java.io.FileNotFoundException: /app/hadoop/tmp/dfs/name/current/VERSION (Permission denied)
at java.io.RandomAccessFile.open(Native Method)
at java.io.RandomAccessFile.<init>(RandomAccessFile.java:233)
at org.apache.hadoop.hdfs.server.common.Storage$StorageDirectory.read(Storage.java:219)
at org.apache.hadoop.hdfs.server.common.Storage$StorageDirectory.read(Storage.java:215)
at org.apache.hadoop.hdfs.server.namenode.FSImage.recoverTransitionRead(FSImage.java:314)
at org.apache.hadoop.hdfs.server.namenode.FSDirectory.loadFSImage(FSDirectory.java:100)
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.initialize(FSNamesystem.java:411)
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.<init>(FSNamesystem.java:379)
at org.apache.hadoop.hdfs.server.namenode.NameNode.initialize(NameNode.java:284)
at org.apache.hadoop.hdfs.server.namenode.NameNode.<init>(NameNode.java:536)
at org.apache.hadoop.hdfs.server.namenode.NameNode.createNameNode(NameNode.java:1410)
at org.apache.hadoop.hdfs.server.namenode.NameNode.main(NameNode.java:1419)
2013-04-11 01:52:59,437 INFO org.apache.hadoop.hdfs.server.namenode.NameNode: SHUTDOWN_MSG:
/************************************************************
SHUTDOWN_MSG: Shutting down NameNode at Master/192.168.7.238
************************************************************/
