Hadoop格式化HDFS报错java.net.UnknownHostException: localhost.localdomain: localhost.localdomain

ゝ一世哀愁。 2022-06-12 12:17 92阅读 0赞

### 异常描述 ###

在对HDFS格式化，执行hadoop namenode -format命令时，出现未知的主机名的问题，异常信息如下所示：

[shirdrn@localhost bin]$ hadoop namenode -format
    11/06/22 07:33:31 INFO namenode.NameNode: STARTUP_MSG: 
    /************************************************************
    STARTUP_MSG: Starting NameNode
    STARTUP_MSG:   host = java.net.UnknownHostException: localhost.localdomain: localhost.localdomain
    STARTUP_MSG:   args = [-format]
    STARTUP_MSG:   version = 0.20.0
    STARTUP_MSG:   build = https://svn.apache.org/repos/asf/hadoop/core/branches/branch-0.20 -r 763504; compiled by 'ndaley' on Thu Apr  9 05:18:40 UTC 2009
    ************************************************************/
    Re-format filesystem in /tmp/hadoop/hadoop-shirdrn/dfs/name ? (Y or N) Y
    11/06/22 07:33:36 INFO namenode.FSNamesystem: fsOwner=shirdrn,shirdrn
    11/06/22 07:33:36 INFO namenode.FSNamesystem: supergroup=supergroup
    11/06/22 07:33:36 INFO namenode.FSNamesystem: isPermissionEnabled=true
    11/06/22 07:33:36 INFO metrics.MetricsUtil: Unable to obtain hostName
    java.net.UnknownHostException: localhost.localdomain: localhost.localdomain
            at java.net.InetAddress.getLocalHost(InetAddress.java:1353)
            at org.apache.hadoop.metrics.MetricsUtil.getHostName(MetricsUtil.java:91)
            at org.apache.hadoop.metrics.MetricsUtil.createRecord(MetricsUtil.java:80)
            at org.apache.hadoop.hdfs.server.namenode.FSDirectory.initialize(FSDirectory.java:73)
            at org.apache.hadoop.hdfs.server.namenode.FSDirectory.<init>(FSDirectory.java:68)
            at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.<init>(FSNamesystem.java:370)
            at org.apache.hadoop.hdfs.server.namenode.NameNode.format(NameNode.java:853)
            at org.apache.hadoop.hdfs.server.namenode.NameNode.createNameNode(NameNode.java:947)
            at org.apache.hadoop.hdfs.server.namenode.NameNode.main(NameNode.java:964)
    11/06/22 07:33:36 INFO common.Storage: Image file of size 97 saved in 0 seconds.
    11/06/22 07:33:36 INFO common.Storage: Storage directory /tmp/hadoop/hadoop-shirdrn/dfs/name has been successfully formatted.
    11/06/22 07:33:36 INFO namenode.NameNode: SHUTDOWN_MSG: 
    /************************************************************
    SHUTDOWN_MSG: Shutting down NameNode at java.net.UnknownHostException: localhost.localdomain: localhost.localdomain
    ************************************************************/

我们通过执行hostname命令可以看到：

[shirdrn@localhost bin]# hostname
    localhost.localdomain

也就是说，Hadoop在格式化HDFS的时候，通过hostname命令获取到的主机名是localhost.localdomain，然后在/etc/hosts文件中进行映射的时候，没有找到，看下我的/etc/hosts内容：

[root@localhost bin]# cat /etc/hosts
    # Do not remove the following line, or various programs
    # that require network functionality will fail.
    127.0.0.1               localhost       localhost
    192.168.1.103           localhost       localhost

也就说，通过localhost.localdomain根本无法映射到一个IP地址，所以报错了。

此时，我们查看一下/etc/sysconfig/network文件：

NETWORKING=yes
    NETWORKING_IPV6=yes
    HOSTNAME=localhost.localdomain

可见，执行hostname获取到这里配置的HOSTNAME的值。

[root@localhost bin]# /etc/rc.d/init.d/network restart
    Shutting down interface eth0:  [  OK  ]
    Shutting down loopback interface:  [  OK  ]
    Bringing up loopback interface:  [  OK  ]
    Bringing up interface eth0:  
    Determining IP information for eth0... done.
    [  OK  ]

这时，再执行格式化HDFS命令，以及启动HDFS集群就正常了。

格式化：

[shirdrn@localhost bin]$ hadoop namenode -format
    11/06/22 08:02:37 INFO namenode.NameNode: STARTUP_MSG: 
    /************************************************************
    STARTUP_MSG: Starting NameNode
    STARTUP_MSG:   host = localhost/127.0.0.1
    STARTUP_MSG:   args = [-format]
    STARTUP_MSG:   version = 0.20.0
    STARTUP_MSG:   build = https://svn.apache.org/repos/asf/hadoop/core/branches/branch-0.20 -r 763504; compiled by 'ndaley' on Thu Apr  9 05:18:40 UTC 2009
    ************************************************************/
    11/06/22 08:02:37 INFO namenode.FSNamesystem: fsOwner=shirdrn,shirdrn
    11/06/22 08:02:37 INFO namenode.FSNamesystem: supergroup=supergroup
    11/06/22 08:02:37 INFO namenode.FSNamesystem: isPermissionEnabled=true
    11/06/22 08:02:37 INFO common.Storage: Image file of size 97 saved in 0 seconds.
    11/06/22 08:02:37 INFO common.Storage: Storage directory /tmp/hadoop/hadoop-shirdrn/dfs/name has been successfully formatted.
    11/06/22 08:02:37 INFO namenode.NameNode: SHUTDOWN_MSG: 
    /************************************************************
    SHUTDOWN_MSG: Shutting down NameNode at localhost/127.0.0.1
    ************************************************************/

启动：

[shirdrn@localhost bin]$ start-all.sh 
    starting namenode, logging to /home/shirdrn/eclipse/eclipse-3.5.2/hadoop/hadoop-0.20.0/logs/hadoop-shirdrn-namenode-localhost.out
    localhost: starting datanode, logging to /home/shirdrn/eclipse/eclipse-3.5.2/hadoop/hadoop-0.20.0/logs/hadoop-shirdrn-datanode-localhost.out
    localhost: starting secondarynamenode, logging to /home/shirdrn/eclipse/eclipse-3.5.2/hadoop/hadoop-0.20.0/logs/hadoop-shirdrn-secondarynamenode-localhost.out
    starting jobtracker, logging to /home/shirdrn/eclipse/eclipse-3.5.2/hadoop/hadoop-0.20.0/logs/hadoop-shirdrn-jobtracker-localhost.out
    localhost: starting tasktracker, logging to /home/shirdrn/eclipse/eclipse-3.5.2/hadoop/hadoop-0.20.0/logs/hadoop-shirdrn-tasktracker-localhost.out

查看：

[shirdrn@localhost bin]$ jps
    8192 TaskTracker
    7905 DataNode
    7806 NameNode
    8065 JobTracker
    8002 SecondaryNameNode
    8234 Jps

此文转自： [http://blog.csdn.net/shirdrn/article/details/6562292][http_blog.csdn.net_shirdrn_article_details_6562292]

[http_blog.csdn.net_shirdrn_article_details_6562292]: http://blog.csdn.net/shirdrn/article/details/6562292