How to configure Elasticsearch own logging?

[WoJ]

Hello everyone,

I centralize all my systems / applications logs in Elasticsearch and one of the most prolific sources is Elasticsearch itself.

I thought that I could lower the verbosity in /etc/elasticsearch/log4j2.properties to warnings only by changing all the levels there to warn (such as logger.action.level = warn) but I keep on getting the log below at each query.

Where can I disable this kind of operational logs?

{
  "type": "response",
  "@timestamp": "2018-09-21T10:45:35Z",
  "tags": [],
  "pid": 30232,
  "method": "post",
  "statusCode": 200,
  "req": {
    "url": "/logtrail/search",
    "method": "post",
    "headers": {
      "host": "10.200.0.1:5601",
      "connection": "keep-alive",
      "content-length": "587",
      "accept": "application/json, text/plain, */*",
      "origin": "http://10.200.0.1:5601",
      "kbn-version": "6.2.4",
      "user-agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.100 Safari/537.36",
      "dnt": "1",
      "content-type": "application/json;charset=UTF-8",
      "referer": "http://10.200.0.1:5601/app/logtrail",
      "accept-encoding": "gzip, deflate",
      "accept-language": "fr-FR,fr;q=0.9,en-XA;q=0.8,en;q=0.7,en-US;q=0.6"
    },
    "remoteAddress": "10.200.0.2",
    "userAgent": "10.200.0.2",
    "referer": "http://10.200.0.1:5601/app/logtrail"
  },
  "res": {
    "statusCode": 200,
    "responseTime": 18,
    "contentLength": 9
  },
  "message": "POST /logtrail/search 200 18ms - 9.0B"
}