Template must not be null – 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 analyzes 2 JSON files to detect many configuration errors.

Briefly, this error message indicates that Elasticsearch is expecting a non-null template, but the provided template is null. Templates are used to specify the structure of an index in Elasticsearch, and are typically defined using the Mustache templating language. To resolve this error, ensure that a valid non-null template is provided when creating an index in Elasticsearch.

To easily locate the root cause and resolve this issue try AutoOps for Elasticsearch & OpenSearch. It diagnoses problems by analyzing hundreds of metrics collected by a lightweight agent and offers guidance for resolving them.

This guide will help you check for common problems that cause the log ” Template must not be null ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: template and plugin.

Log Context

Log “Template must not be null”classname  is TemplateUtils.java We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 * Parses and validates that the source is not empty.
 public static void validate(String source) {
 if (source == null) {
 throw new ElasticsearchParseException("Template must not be null");
 if (Strings.isEmpty(source)) {
 throw new ElasticsearchParseException("Template must not be empty");


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