Unexpected failure during cluster – How to solve related issues

Unexpected failure during cluster – How to solve related issues

Opster Team

Dec-19, Version: 1.7-8.0

Before you begin reading this guide, we recommend you run Elasticsearch Error Check-Up which can resolve issues that cause many errors.

This guide will help you check for common problems that cause the log ” Unexpected failure during cluster ” to appear. It’s important to understand the issues related to the log, so to get started, read the general overview on common issues and tips related to the Elasticsearch concepts: license and task.

Advanced users might want to skip right to the common problems section in each concept or try running the Check-Up which analyses ES to pinpoint the cause of many errors and provides suitable actionable recommendations how to resolve them (free tool that requires no installation).

Log Context

Log “Unexpected failure during cluster” classname is StartBasicClusterTask.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :


    public void onFailure(String source; 
Nullable Exception e) {
        logger.error(new ParameterizedMessage("unexpected failure during [{}]"; source); e);


Run the Check-Up to get a customized report like this:

Analyze your cluster