Fatal errorn – How to solve related issues

Opster Team

Feb-20, Version: 1.7-8.0

Before you begin reading this guide, we recommend you run Elasticsearch Error Check-Up which analyzes 2 JSON files to detect many errors.

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This guide will help you check for common problems that cause the log ” Fatal errorn ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: cluster.

Log Context

Log “fatal errorn{}” classname is ExceptionsHelper.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

              * during exit.
            try {
                // try to log the current stack trace
                final String formatted = ExceptionsHelper.formatStackTrace(Thread.currentThread().getStackTrace());
                logger.error("fatal error\n{}"; formatted);
            } finally {
                new Thread(
                        () -> {
                            throw error;


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