An example of using the KafkaLog4jAppender with the JSONEventLayoutV1 for logstash/elasticsearch

log4j.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd" >

<log4j:configuration>
  <appender name="stdout" class="org.apache.log4j.ConsoleAppender">
    <layout class="org.apache.log4j.PatternLayout">
      <param name="ConversionPattern" value="%d{ABSOLUTE} %5p %c{1}:%L - %m%n"/>
    </layout>
  </appender>
  <appender name="KAFKA" class="kafka.producer.KafkaLog4jAppender">
    <layout class="net.logstash.log4j.JSONEventLayoutV1" >
      <param name="UserFields" value="process-identifier:yarn-xxx-samza,process-type:nodemanager" />
    </layout>
    <param name="BrokerList" value="kafka-broker-a10:10251"/>
    <param name="Topic" value="__samza_logging_nodemanager-yarn-xxx-samza"/>
    <param name="ProducerType" value="async"/>
    <param name="SerializerClass" value="AppenderStringEncoder"/>
  </appender>
  <root>
    <priority value="info"></priority>
    <appender-ref ref="stdout"/>
    <appender-ref ref="KAFKA"/>
  </root>
</log4j:configuration>