On our servers, the /var/log/messages file is flooded with messages like this:
Jun 10 08:16:46 SERVER logstash: 2020-06-10 08:16:42,551 Converge PipelineAction::Create<logstash_job_name> WARN The Logger slowlog.logstash.filters.date was created with the message factory org.apache.logging.log4j.spi.MessageFactory2Adapter@696374d1 and is now requested with a null message factory (defaults to org.logstash.log.LogstashMessageFactory), which may create log events with unexpected formatting.
For almost every input, filter, output plugin for every job and many times until the logstash start. Sometimes the start process after restart took more 10 minutes.
We have tried many thinks like to setup /etc/logstash/log4j2.properties, check the ownership of the file etc. but the messages log is still flooded.
The logstash on our servers is in 7.6.0 version