Failed to parse aliases – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-8.9

Briefly, this error occurs when Elasticsearch is unable to interpret the alias configuration due to incorrect syntax or structure. This could be due to a missing or misplaced bracket, incorrect indentation, or a typo in the alias name. To resolve this issue, you should first check the alias configuration for any syntax errors. If the syntax is correct, verify that the alias name is spelled correctly and does not contain any special characters. Lastly, ensure that the alias is not already in use, as Elasticsearch does not allow duplicate aliases.

This guide will help you check for common problems that cause the log ” Failed to parse aliases ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: admin, aliases, template, indices.

Log Context

Log “Failed to parse aliases” class name is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 while ((parser.nextToken()) != XContentParser.Token.END_OBJECT) {
 return this;
 } catch (IOException e) {
 throw new ElasticsearchParseException("Failed to parse aliases"; e);
 }  /**
 * Adds an alias that will be added when the index gets created.