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

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Unknown key in the template – 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 ” unknown key in the template ” 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: admin, indices and template.

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”unknown key [{}] in the template”classname  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;


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

Analyze your cluster