Unexpected failure during node-left – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 8.1-8.2

Briefly, this error occurs when a node in the Elasticsearch cluster unexpectedly leaves or disconnects. This could be due to network issues, hardware failure, or the node being overloaded. To resolve this issue, you can try the following: 1) Check the network connectivity between the nodes. 2) Monitor the hardware resources of the node that left, it might be overloaded. 3) Check the Elasticsearch logs for any specific errors related to the node leaving. 4) If the node is consistently leaving, consider adding more nodes to the cluster to distribute the load.

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

Log Context

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

    public record Task(DiscoveryNode node; String reason; Runnable onClusterStateProcessed) implements ClusterStateTaskListener {

        public void onFailure(final Exception e) {
            logger.error("unexpected failure during [node-left]"; e);

        public void onNoLongerMaster() {
            logger.debug("no longer master while processing node removal [node-left]");


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