2.2. Enabling Logging

To enable logging change the settings in the hadoop-env.cmd. After modifying the hadoop-env.cmd, recreate the NameNode service XML and then restart the NameNode.

	Note
	To enable audit logging change the hdfs.audit.logger value to INFO,RFAAUDIT and then overwrite the NameNode service XML and restart the NameNode.

Open the Hadoop Environment script, %HADOOP_HOME%\etc\hadoop\hadoop-env.cmd.

Prepend the following text in the HADOOP_NAMENODE_OPTS definition, for example to enable Garbage Collection logging:

-Xloggc:%HADOOP_LOG_DIR%/gc-namenode.log -verbose:gc -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+PrintGCDateStamps

For example:

set HADOOP_NAMENODE_OPTS=-Xloggc:%HADOOP_LOG_DIR%/gc-namenode.log -verbose:gc -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+PrintGCDateStamps -Dhadoop.security.logger=%HADOOP_SECURITY_LOGGER% -Dhdfs.audit.logger=%HDFS_AUDIT_LOGGER% %HADOOP_NAMENODE_OPTS%

Run the following command to recreate the NameNode service XML:
```
%HADOOP_HOME%\bin\hdfs.cmd --service namenode > %HADOOP_HOME%\bin\namenode.xml
```
Verify that the NameNode Service XML was updated.
Restart the NameNode service.

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