Can’t connect 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 connect 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 connect to a null node”classname  is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

public void connectToNode(DiscoveryNode node; ConnectionProfile connectionProfile;
 ConnectionValidator connectionValidator;
 ActionListener listener) throws ConnectTransportException {
 ConnectionProfile resolvedProfile = ConnectionProfile.resolveConnectionProfile(connectionProfile; defaultProfile);
 if (node == null) {
 listener.onFailure(new ConnectTransportException(null; "can't connect to a null node"));
 if (connectingRefCounter.tryIncRef() == false) {
 listener.onFailure(new IllegalStateException("connection manager is closed"));


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