Storm in a Clustered Mode - Real-time Analytics with Storm and Cassandra - page 76

Storm logging configurations
Now we will have a look at the logging configurations of Storm. They use the logback
implementation of Log4J and its configurations can be found and tweaked from
cluster.xml located at <storm-installation-dir>/apache-
storm-0.9.2-incubating/logback using the following code:
<appender name="A1"
class="ch.qos.logback.core.rolling.RollingFileAppender">
<file>${storm.log.dir}/${logfile.name}</file>
<rollingPolicy
class="ch.qos.logback.core.rolling.FixedWindowRollingPolicy">
<fileNamePattern>${storm.log.dir}/
${logfile.name}.%i</fileNamePattern >
<minIndex>1</minIndex>
<maxIndex>9</maxIndex>
</rollingPolicy>
<triggeringPolicy
class="ch.qos.logback.core.rolling.SizeBasedTriggeringPolicy">
<maxFileSize>100MB</maxFileSize>
</triggeringPolicy>
<encoder>
<pattern>%d{yyyy-MM-dd HH:mm:ss} %c{1} [%p]
%m%n</pattern>
</encoder>
</appender>
<root level="INFO">
<appender-ref ref="A1"/>
</root>
In the preceding snippet, a few sections are highlighted, which we will walk through for a
closer look. They are as follows:
• <file> : This tag holds the log directory path and the filename on which the logs
are generated by the Storm framework.