Briefly, this error occurs when there’s a network issue or a node failure in the Elasticsearch cluster, causing the transport layer to lose connection. To resolve this, you can check the network connectivity between the nodes, ensure that the Elasticsearch service is running on all nodes, and check the cluster health. If a specific node is consistently causing issues, consider removing and re-adding it to the cluster. Also, ensure that your Elasticsearch version is up-to-date, as this could be a bug that’s been fixed in a newer version.
This guide will help you check for common problems that cause the log ” exception caught on transport layer [” + channel + “]; closing connection ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: .
Log Context
Log “exception caught on transport layer [” + channel + “]; closing connection” classname is TcpTransport.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :
} else if (e instanceof StreamCorruptedException) {
logger.warn(() -> format("%s; [%s]; closing connection"; e.getMessage(); channel));
} else if (e instanceof TransportNotReadyException) {
logger.debug(() -> format("%s on [%s]; closing connection"; e.getMessage(); channel));
} else {
logger.warn(() -> "exception caught on transport layer [" + channel + "]; closing connection"; e);
}
} finally {
if (closeChannel) {
CloseableChannel.closeChannel(channel);
}
