custom log4j class is not working over spark 2.0 EMR

Question

i am trying to write logs as json in spark 2.0 over EMR. i was able to use custom log4j.properties file.

but when i tried to change the output to json with custom class (net.logstash.log4j.JSONEventLayoutV1), i get the following exception:

log4j:ERROR Could not instantiate class [net.logstash.log4j.JSONEventLayoutV1].
java.lang.ClassNotFoundException: net.logstash.log4j.JSONEventLayoutV1
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:264)
    at org.apache.log4j.helpers.Loader.loadClass(Loader.java:198)
    at org.apache.log4j.helpers.OptionConverter.instantiateByClassName(OptionConverter.java:327)
    at org.apache.log4j.helpers.OptionConverter.instantiateByKey(OptionConverter.java:124)
    at org.apache.log4j.PropertyConfigurator.parseAppender(PropertyConfigurator.java:797)
    at org.apache.log4j.PropertyConfigurator.parseCategory(PropertyConfigurator.java:768)
    at org.apache.log4j.PropertyConfigurator.configureRootCategory(PropertyConfigurator.java:648)
    at org.apache.log4j.PropertyConfigurator.doConfigure(PropertyConfigurator.java:514)
    at org.apache.log4j.PropertyConfigurator.doConfigure(PropertyConfigurator.java:580)
    at org.apache.log4j.helpers.OptionConverter.selectAndConfigure(OptionConverter.java:526)
    at org.apache.log4j.LogManager.<clinit>(LogManager.java:127)
    at org.apache.spark.internal.Logging$class.initializeLogging(Logging.scala:117)
    at org.apache.spark.internal.Logging$class.initializeLogIfNecessary(Logging.scala:102)
    at org.apache.spark.executor.CoarseGrainedExecutorBackend$.initializeLogIfNecessary(CoarseGrainedExecutorBackend.scala:161)
    at org.apache.spark.internal.Logging$class.log(Logging.scala:46)
    at org.apache.spark.executor.CoarseGrainedExecutorBackend$.log(CoarseGrainedExecutorBackend.scala:161)
    at org.apache.spark.executor.CoarseGrainedExecutorBackend$.run(CoarseGrainedExecutorBackend.scala:172)
    at org.apache.spark.executor.CoarseGrainedExecutorBackend$.main(CoarseGrainedExecutorBackend.scala:270)
    at org.apache.spark.executor.CoarseGrainedExecutorBackend.main(CoarseGrainedExecutorBackend.scala)

here is how the log4j.properties, looks like:

log4j.rootCategory=INFO, json

log4j.appender.json=org.apache.log4j.ConsoleAppender 
log4j.appender.json.target=System.err 
log4j.appender.json.layout=net.logstash.log4j.JSONEventLayoutV1

The artifact "jsonevent-layout", was assembled in the fat-jar.

Does anyone has a clue how to solve this issue ?

thanks, Eran

Answer 1

eventually, this worked for me:

log4j.rootCategory=INFO, json

log4j.appender.json=org.apache.log4j.ConsoleAppender
log4j.appender.json.target=System.err
log4j.appender.json.layout=org.apache.hadoop.log.Log4Json