No connection available – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 8.8-8.9

Briefly, this error occurs when Elasticsearch cannot establish a connection due to network issues, incorrect configuration, or the Elasticsearch service not running. To resolve this, ensure the Elasticsearch service is running and reachable. Check your network connection and firewall settings. Verify your Elasticsearch configuration, specifically the host and port settings. If you’re using a cluster, ensure all nodes are operational and networked correctly.

This guide will help you check for common problems that cause the log ” No connection available ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: cluster.

Log Context

Log “No connection available” class name is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 private void sendFullClusterState(DiscoveryNode destination; ActionListener listener) {
 assert refCount() > 0;
 Transport.Connection connection = nodeConnections.get(destination);
 if (connection == null) {
 logger.debug("No connection to [{}] available; skipping send"; destination);
 listener.onFailure(new NodeNotConnectedException(destination; "No connection available"));
 }  var version = connection.getTransportVersion();
 ReleasableBytesReference bytes = serializedStates.get(version);


How helpful was this guide?

We are sorry that this post was not useful for you!

Let us improve this post!

Tell us how we can improve this post?