Unexpected failure during – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 6.8-8.2

Briefly, this error occurs when Elasticsearch encounters an unexpected issue during its operation. This could be due to a variety of reasons such as insufficient memory, corrupted data, or network issues. To resolve this, you can try increasing the memory allocation for Elasticsearch, checking the integrity of your data, or troubleshooting your network connection. Additionally, you can check the Elasticsearch logs for more detailed information about the error, which can help in identifying the root cause and finding a suitable solution.

This guide will help you check for common problems that cause the log ” unexpected failure during [{}] ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: admin, cluster.

Log Context

Log “unexpected failure during [{}]” classname is TransportClusterHealthAction.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :


                public void onFailure(Exception e) {
                    logger.error(() -> new ParameterizedMessage("unexpected failure during [{}]"; source); e);
            }.submit(clusterService.getMasterService(); source);
        } else {
            final TimeValue taskTimeout = TimeValue.timeValueMillis(Math.max(0; endTimeRelativeMillis - threadPool.relativeTimeInMillis()));