hadoop Incompatible namespaceIDs异常

张颢镡

　　在自己的虚拟机上重新编译hadoop-0.20.2-cdh3u3后启动hadoop, 发现datanode没有起来.
　　

• [hadoop@localhost bin]$ hadoop dfsadmin -report
  
• Configured Capacity: 0 (0 KB)
  
• Present Capacity: 0 (0 KB)
  
• DFS Remaining: 0 (0 KB)
  
• DFS Used: 0 (0 KB)
  
• DFS Used%: 锟?
  
• Under replicated blocks: 0
  
• Blocks with corrupt replicas: 0
  
• Missing blocks: 0
  
• 
  
• -------------------------------------------------
  
• Datanodes available: 0 (0 total, 0 dead)
  

　　

　　转到日志目录， 查看datanode日志,发现如下异常:
　　

• 2012-03-27 18:20:12,275 INFO org.apache.hadoop.security.UserGroupInformation: JAAS Configuration already set up for Hadoop, not re-installing. 2012-03-27 18:20:12,334 ERROR org.apache.hadoop.hdfs.server.datanode.DataNode: java.io.IOException: Incompatible namespaceIDs in /opt/hdfs1: namenode namespaceID = 2020402075; datanode namespaceID = 728558412 at org.apache.hadoop.hdfs.server.datanode.DataStorage.doTransition(DataStorage.java:238) at org.apache.hadoop.hdfs.server.datanode.DataStorage.recoverTransitionRead(DataStorage.java:153) at org.apache.hadoop.hdfs.server.datanode.DataNode.startDataNode(DataNode.java:410) at org.apache.hadoop.hdfs.server.datanode.DataNode.(DataNode.java:305) at org.apache.hadoop.hdfs.server.datanode.DataNode.makeInstance(DataNode.java:1606) at org.apache.hadoop.hdfs.server.datanode.DataNode.instantiateDataNode(DataNode.java:1546) at org.apache.hadoop.hdfs.server.datanode.DataNode.createDataNode(DataNode.java:1564) at org.apache.hadoop.hdfs.server.datanode.DataNode.secureMain(DataNode.java:1690) at org.apache.hadoop.hdfs.server.datanode.DataNode.main(DataNode.java:1707)  2012-03-27 18:20:12,334 INFO org.apache.hadoop.hdfs.server.datanode.DataNode: SHUTDOWN_MSG:  /************************************************************ SHUTDOWN_MSG: Shutting down DataNode at localhost.localdomain/127.0.0.1 ************************************************************/
  

　　

　　datanode下的 namespaceID  与namenode的 namespaceID  不一致导致
　　
    看下namenode下 VERSION
　　

• [hadoop@localhost current]$ pwd
  
• /opt/tmp/hadoop-hadoop/dfs/name/current
  
• [hadoop@localhost current]$
  
• [hadoop@localhost current]$ cat VERSION
  
• #Tue Mar 27 18:22:11 PDT 2012
  
• namespaceID=2020402075
  
• cTime=0
  
• storageType=NAME_NODE
  
• layoutVersion=-19
  

　　

　　对比datanode下VERSION
　　

• [hadoop@localhost current]$ pwd
  
• /opt/hdfs1/current
  
• [hadoop@localhost current]$ cat VERSION
  
• #Tue Mar 27 18:16:39 PDT 2012
  
• namespaceID=728558412
  
• storageID=DS-1857008061-127.0.0.1-50010-1330145936216
  
• cTime=0
  
• storageType=DATA_NODE
  
• layoutVersion=-19
  

　　

　　编辑datanode下的VERSION,使 namespaceID 值与namenode下的值相同, 重新启动datanode
　　
    验证:
　　

• [hadoop@localhost bin]$ hadoop dfsadmin -report
  
• Configured Capacity: 366965649408 (341.76 GB)
  
• Present Capacity: 334563717120 (311.59 GB)
  
• DFS Remaining: 334563618816 (311.59 GB)
  
• DFS Used: 98304 (96 KB)
  
• DFS Used%: 0%
  
• Under replicated blocks: 0
  
• Blocks with corrupt replicas: 0
  
• Missing blocks: 0
  
• 
  
• -------------------------------------------------
  
• Datanodes available: 1 (1 total, 0 dead)
  
• 
  
• Name: 192.168.189.128:50010
  
• Decommission Status : Normal
  
• Configured Capacity: 366965649408 (341.76 GB)
  
• DFS Used: 98304 (96 KB)
  
• Non DFS Used: 32401932288 (30.18 GB)
  
• DFS Remaining: 334563618816(311.59 GB)
  
• DFS Used%: 0%
  
• DFS Remaining%: 91.17%
  
• Last contact: Tue Mar 27 18:25:11 PDT 2012
  

　　

　　可以看到，datanode已经起来!