closing connection – 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.

Briefly, this error message indicates that a connection is being closed. The reason for this could be due to a deliberate action or a problem with the Elasticsearch instance. To resolve the issue, the reason for the connection being closed should be determined and addressed accordingly.

To easily locate the root cause and resolve this issue try AutoOps for Elasticsearch & OpenSearch. It diagnoses problems by analyzing hundreds of metrics collected by a lightweight agent and offers guidance for resolving them.

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

Log Context

Log “{}; [{}]; closing connection” classname is
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

             if (channel.isOpen()) {
                BytesArray message = new BytesArray(e.getMessage().getBytes(StandardCharsets.UTF_8));
                outboundHandler.sendBytes(channel; message; ActionListener.wrap(() -> CloseableChannel.closeChannel(channel)));
        } else if (e instanceof StreamCorruptedException) {
            logger.warn(() -> new ParameterizedMessage("{}; [{}]; closing connection"; e.getMessage(); channel));
        } else {
            logger.warn(() -> new ParameterizedMessage("exception caught on transport layer [{}]; closing connection"; channel); e);
            // close the channel; which will cause a node to be disconnected if relevant


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