Disconnected during check – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 7.3-7.15

Briefly, this error occurs when Elasticsearch loses connection during a health check or data transfer. This could be due to network issues, high load on the Elasticsearch cluster, or a faulty node. To resolve this, you can try the following: 1) Check your network connectivity and ensure it’s stable. 2) Monitor the load on your Elasticsearch cluster and scale it up if necessary. 3) Identify and replace any faulty nodes in your cluster. 4) Increase the timeout settings if the operations are expected to take longer.

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

Log Context

Log “disconnected during check” class name is LeaderChecker.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 }  if (exp instanceof ConnectTransportException || exp.getCause() instanceof ConnectTransportException) {
 logger.debug(new ParameterizedMessage(
 "leader [{}] disconnected during check"; leader); exp);
 leaderFailed(new ConnectTransportException(leader; "disconnected during check"; exp));
 } else if (exp.getCause() instanceof NodeHealthCheckFailureException) {
 logger.debug(new ParameterizedMessage(
 "leader [{}] health check failed"; leader); exp);
 leaderFailed(new NodeHealthCheckFailureException("node [" + leader + "] failed health checks"; exp));


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