Hadoop常见问题及解决方法汇总

我会带着你远行 2022-09-04 02:56 992阅读 0赞

### 1、ERROR: Unable to write in /opt/hadoop-3.3.0/logs. Aborting. Starting datanodes ###

**解决：`sudo chown -R hadoop:hadoop /usr/local/hadoop`**

### 2、790 WARN util.NativeCodeLoader: Unable to load native-hadoop library for you ###

**解决：`/opt/hadoop-3.3.0/etc/hadoop/log4j.properties添加log4j.logger.org.apache.hadoop.util.NativeCodeLoader=ERROR`**

### 3、localhost: ERROR: Cannot set priority of datanode process ###

hdfs-site.xml添加

<property>
            <name>dfs.name.dir</name>
            <value>/opt/hadoop-3.3.0/hdfsDir/name</value>
            <description>datanode上存储hdfs名字空间元数据</description>
          </property>
         <property>
            <name>dfs.data.dir</name>
            <value>/opt/hadoop-3.3.0/hdfsDir/data</value>
            <description>datanode上数据块的物理存储位置</description>
         </property>

### 4、Cannot create xxx/xxx.txt. Name node is in safe mode. ###

hadoop dfsadmin -safemode leave

### 5、There are 0 datanode(s) running and 0 node(s) are excluded in this operation. ###

**找到hadoop安装目录下./data/dfs/data里面的current文件夹删除  
然后从新执行一下 `hadoop namenode -format`**

### 6、ERROR org.apache.hadoop.hdfs.server.namenode.SecondaryNameNode: Failed to start secondary namenode ###

hadoop文件夹下的data和name文件夹里面的current/version，发现clusterID不一致.  
错误原因：**多次错误初始化NameNode，导致namenode和datanode的namespaceID和clusterID不一致**

**解决方法：删除hdfs中配置的data目录下的所有文件（core-site.xml中配置的hadoop.tmp.dir）  
1、删除Hadoop文件夹…/tmp/dfs 里面的data和name文件夹  
2、初始化NameNode：hdfs namenode -format  
3、启动HDFS：start-dfs.sh**