Data Prepper uses SLF4J with a Log4j 2 binding.
Default properties for Log4j 2 can be found in the log4j2.properties file in the shared-config directory.
Users are able to override these logging settings by setting their own "log4j.configurationFile" system property (see Log4j 2 configuration docs).
Example:
java "-Dlog4j.configurationFile=config/custom-log4j2.properties" -jar data-prepper-core-$VERSION.jar pipelines.yaml data-prepper-config.yaml