Can’t open connection to a null node – How to solve this Elasticsearch error

Opster Team

July-20, Version: 1.7-8.0

Before you begin reading this guide, we recommend you try running the Elasticsearch Check-Up which can resolve issues that cause many errors.

This guide will help you check for common problems that cause the log ” can’t open connection to a null node ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: node.

Advanced users might want to skip right to the common problems section in each concept or try running the Check-Up to analyze Elasticsearch configuration and help resolve this error.

Log Context

Log “can’t open connection to a null node”classname  is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 public void openConnection(DiscoveryNode node; ConnectionProfile profile; ActionListener listener) { 
 Objects.requireNonNull(profile; "connection profile cannot be null");
 if (node == null) {
 throw new ConnectTransportException(null; "can't open connection to a null node");
 ConnectionProfile finalProfile = maybeOverrideConnectionProfile(profile);
 closeLock.readLock().lock(); // ensure we don't open connections while we are closing
 try {


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