Hadoop datanode无法开始抛出org.apache.hadoop.hdfs.server.common.Storage：无法锁定存储

Question

I have some problems trying to start a datanode in Hadoop, from the log I can see that datanode is started twice (partial log follows):

2012-05-22 16:25:00,369 INFO org.apache.hadoop.hdfs.server.datanode.DataNode: STARTUP_MSG: 
/************************************************************
STARTUP_MSG: Starting DataNode
STARTUP_MSG:   host = master/192.168.0.1
STARTUP_MSG:   args = []
STARTUP_MSG:   version = 1.0.1
STARTUP_MSG:   build = https://svn.apache.org/repos/asf/hadoop/common/branches/branch-1.0 -r 1243785; compiled by 'hortonfo' on Tue Feb 14 08:15:38 UTC 2012
************************************************************/
2012-05-22 16:25:00,375 INFO org.apache.hadoop.hdfs.server.datanode.DataNode: STARTUP_MSG: 
/************************************************************
STARTUP_MSG: Starting DataNode
STARTUP_MSG:   host = master/192.168.0.1
STARTUP_MSG:   args = []
STARTUP_MSG:   version = 1.0.1
STARTUP_MSG:   build = https://svn.apache.org/repos/asf/hadoop/common/branches/branch-1.0 -r 1243785; compiled by 'hortonfo' on Tue Feb 14 08:15:38 UTC 2012
************************************************************/
2012-05-22 16:25:00,490 INFO org.apache.hadoop.metrics2.impl.MetricsConfig: loaded properties from hadoop-metrics2.properties
2012-05-22 16:25:00,500 INFO org.apache.hadoop.metrics2.impl.MetricsSourceAdapter: MBean for source MetricsSystem,sub=Stats registered.
2012-05-22 16:25:00,500 INFO org.apache.hadoop.metrics2.impl.MetricsSystemImpl: Scheduled snapshot period at 10 second(s).
2012-05-22 16:25:00,500 INFO org.apache.hadoop.metrics2.impl.MetricsSystemImpl: DataNode metrics system started
2012-05-22 16:25:00,512 INFO org.apache.hadoop.metrics2.impl.MetricsConfig: loaded properties from hadoop-metrics2.properties
2012-05-22 16:25:00,523 INFO org.apache.hadoop.metrics2.impl.MetricsSourceAdapter: MBean for source MetricsSystem,sub=Stats registered.
2012-05-22 16:25:00,523 INFO org.apache.hadoop.metrics2.impl.MetricsSystemImpl: Scheduled snapshot period at 10 second(s).
2012-05-22 16:25:00,524 INFO org.apache.hadoop.metrics2.impl.MetricsSystemImpl: DataNode metrics system started
2012-05-22 16:25:00,722 INFO org.apache.hadoop.metrics2.impl.MetricsSourceAdapter: MBean for source ugi registered.
2012-05-22 16:25:00,724 INFO org.apache.hadoop.metrics2.impl.MetricsSourceAdapter: MBean for source ugi registered.
2012-05-22 16:25:00,727 WARN org.apache.hadoop.metrics2.impl.MetricsSystemImpl: Source name ugi already exists!
2012-05-22 16:25:00,729 WARN org.apache.hadoop.metrics2.impl.MetricsSystemImpl: Source name ugi already exists!
2012-05-22 16:20:15,894 INFO org.apache.hadoop.hdfs.server.common.Storage: Cannot lock storage /app/hadoop/tmp/dfs/data. The directory is already locked.
2012-05-22 16:20:16,008 ERROR org.apache.hadoop.hdfs.server.datanode.DataNode: java.io.IOException: Cannot lock storage /app/hadoop/tmp/dfs/data. The directory is already locked.
        at org.apache.hadoop.hdfs.server.common.Storage$StorageDirectory.lock(Storage.java:602)
        at org.apache.hadoop.hdfs.server.common.Storage$StorageDirectory.analyzeStorage(Storage.java:455)
        at org.apache.hadoop.hdfs.server.datanode.DataStorage.recoverTransitionRead(DataStorage.java:111)
        at org.apache.hadoop.hdfs.server.datanode.DataNode.startDataNode(DataNode.java:385)
        at org.apache.hadoop.hdfs.server.datanode.DataNode.<init>(DataNode.java:299)
        at org.apache.hadoop.hdfs.server.datanode.DataNode.makeInstance(DataNode.java:1582)
        at org.apache.hadoop.hdfs.server.datanode.DataNode.instantiateDataNode(DataNode.java:1521)
        at org.apache.hadoop.hdfs.server.datanode.DataNode.createDataNode(DataNode.java:1539)
        at org.apache.hadoop.hdfs.server.datanode.DataNode.secureMain(DataNode.java:1665)
        at org.apache.hadoop.hdfs.server.datanode.DataNode.main(DataNode.java:1682)

I've searched online and I found this question , but I didn't overwrite anything using conf/hdfs-site.xml, that is shown below, so Hadoop should use default values that (as described here ) cannot cause any failed lock. This is my conf/hdfs-site.xml:

<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>

<!-- Put site-specific property overrides in this file. -->

<configuration>
  <property>
    <name>dfs.replication</name>
    <value>2</value>
    <description>Default block replication.
    The actual number of replications can be specified when the file is created.
    The default is used if replication is not specified in create time.
    </description>
  </property>
</configuration>

This is my conf/core-site.xml:

<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>

<!-- Put site-specific property overrides in this file. -->

<configuration>
  <property>
    <name>hadoop.tmp.dir</name>
    <value>/app/hadoop/tmp</value>
    <description>A base for other temporary directories.</description>
  </property>

  <property>
    <name>fs.default.name</name>
    <value>hdfs://master:54310</value>
    <description>The name of the default file system.  A URI whose
    scheme and authority determine the FileSystem implementation.  The
    uri's scheme determines the config property (fs.SCHEME.impl) naming
    the FileSystem implementation class.  The uri's authority is used to
    determine the host, port, etc. for a filesystem.</description>
  </property>
</configuration>

This is the content of hadoop/conf/slaves:

master
slave

Answer 1

• stop datanode
• remove the in_use.lock file from the dfs data dir
• location and start datanode

it should work just fine

Answer 2

Also add the following 2 properties in your hdfs-site.xml file..

<property>
        <name>dfs.name.dir</name>
        <value>/some_path</value>
    </property>

    <property>
        <name>dfs.data.dir</name>
        <value>/some_path</value>
    </property>

their default location is /tmp..because of this you lose data on each restart.

Answer 3

I was facing a similar issue, but I read a post that said the dfs.name.dir and dfs.data.dir should be different from each other. I had the two to be the same, and changing these values to be different from each other fixed my issue.

Answer 4

我有同样的问题，并在shell中将umask设置为0022，我在运行测试时为我解决了问题。

Answer 5

sudo rm -r /tmp/hadoop-[YourNameHere]/dfs/data/

并重新启动dfs。