Fetching nodes from external cluster clusterAlias failed – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 8.3-8.9

Briefly, this error occurs when Elasticsearch is unable to retrieve nodes from an external cluster identified by the given clusterAlias. This could be due to network issues, incorrect clusterAlias, or the external cluster being down. To resolve this, ensure the external cluster is up and running, check the network connectivity between the clusters, and verify the clusterAlias is correct. Also, check the Elasticsearch logs for more detailed error information.

This guide will help you check for common problems that cause the log ” fetching nodes from external cluster [” + clusterAlias + “] failed ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: alias, cluster.

Log Context

Log “fetching nodes from external cluster [” + clusterAlias + “] failed” classname is SniffConnectionStrategy.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

            final Consumer onFailure = e -> {
                if (isRetryableException(e) && seedNodesSuppliers.hasNext()) {
                    logger.debug(() -> "fetching nodes from external cluster [" + clusterAlias + "] failed moving to next seed node"; e);
                    collectRemoteNodes(seedNodesSuppliers; listener);
                } else {
                    logger.warn(() -> "fetching nodes from external cluster [" + clusterAlias + "] failed"; e);

            final DiscoveryNode seedNode = seedNodesSuppliers.next().get();


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?