Key settings must be an object – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 7.4-8.9

Briefly, this error occurs when the Elasticsearch configuration file (elasticsearch.yml) contains incorrect formatting. The “settings” field in the configuration file should be an object, meaning it should contain key-value pairs enclosed in curly braces {}. If it’s not formatted correctly, Elasticsearch will throw this error. To resolve this issue, you should review your configuration file and ensure that the “settings” field is correctly formatted as an object. Also, ensure that all nested fields under “settings” are correctly indented and formatted.

This guide will help you check for common problems that cause the log ” key [settings] must be an object ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: admin, indices.

Log Context

Log “key [settings] must be an object” class name is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 public CreateIndexRequest source(Map source; DeprecationHandler deprecationHandler) {
 for (Map.Entry entry : source.entrySet()) {
 String name = entry.getKey();
 if (SETTINGS.match(name; deprecationHandler)) {
 if (entry.getValue() instanceof Map == false) {
 throw new ElasticsearchParseException("key [settings] must be an object");
 settings((Map) entry.getValue());
 } else if (MAPPINGS.match(name; deprecationHandler)) {
 Map mappings = (Map) entry.getValue();
 for (Map.Entry entry1 : mappings.entrySet()) {


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