Unknown key in the template – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-8.9

Briefly, this error occurs when Elasticsearch encounters an unrecognized key in the index template. This could be due to a typo, incorrect syntax, or usage of a key that is not supported in the current version of Elasticsearch. To resolve this issue, you should first verify the keys used in your template against the Elasticsearch documentation for your version. Ensure that the keys are correctly spelled and properly formatted. If the error persists, consider updating your Elasticsearch version or modifying your template to exclude the problematic key.

This guide will help you check for common problems that cause the log ” unknown key [{}] in the template ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: admin, template, indices.

Log Context

Log “unknown key [{}] in the template” class name is PutIndexTemplateRequest.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 mapping((Map) entry1.getValue());
 } else if (name.equals("aliases")) {
 aliases((Map) entry.getValue());
 } else {
 throw new ElasticsearchParseException("unknown key [{}] in the template "; name);
 return this;