How to do it…

In the config directory in your Elasticsearch install directory, there is a log4j2.properties file that controls the working settings.

The steps that are required for changing the logging settings are as follows:

  1. To emit every kind of logging Elasticsearch could produce, you can change the current root level logging, which is as follows:
rootLogger.level = info
  1. This needs to be changed to the following:
rootLogger.level = debug
  1. Now, if you start Elasticsearch from the command line (with bin/elasticsearch -f), you should see a lot of information, like the following, which is not always useful (except to debug unexpected issues):