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

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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 Error 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. It’s important to understand the issues related to the log, so to get started, read the general overview on common issues and tips related to the Elasticsearch concepts: node.

Advanced users might want to skip right to the common problems section in each concept or try running the Check-Up which analyses ES to pinpoint the cause of many errors and provides suitable actionable recommendations how to resolve them (free tool that requires no installation).

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"));


Run the Check-Up to get a customized report like this:

Analyze your cluster