Briefly, this error occurs when Elasticsearch fails to acknowledge the addition of a legacy template. This could be due to a variety of reasons such as network issues, insufficient permissions, or a problem with the template itself. To resolve this issue, you can try the following: 1) Check your network connection and ensure Elasticsearch is running properly. 2) Verify that you have the necessary permissions to add a template. 3) Review the template for any errors or inconsistencies. 4) If the problem persists, consider upgrading to a newer version of Elasticsearch as legacy templates are deprecated in newer versions.
This guide will help you check for common problems that cause the log ” error adding legacy template [{}] for [{}]; request was not acknowledged ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: template, request, plugin.
If you want to learn more about Elasticsearch templates, check out this guide.
Overview
A template in Elasticsearch falls into one of the two following categories and is indexed inside Elasticsearch using its dedicated endpoint:
- Index templates, which are a way to define a set of rules including index settings, mappings and an index pattern. The template is applied automatically whenever a new index is created with the matching pattern. Templates are also used to dynamically apply custom mapping for the fields which are not predefined inside existing mapping.
- Search templates, which help in defining templates for search queries using mustache scripting language. These templates act as a placeholder for variables defined inside the search queries.
Examples
Create a dynamic index template
PUT /_template/template_1?pretty
{
"index_patterns": [
"logs*",
"api*"
],
"settings": {
"number_of_shards": 2
},
"mappings": {
"dynamic_templates": [
{
"strings": {
"match_mapping_type": "string",
"mapping": {
"type": "keyword"
}
}
}
],
"properties": {
"host_name": {
"type": "keyword"
},
"created_at": {
"type": "date"
}
}
}
}Create a search template
POST /_scripts/search_template_1?pretty
{
"script": {
"lang": "mustache",
"source": {
"query": {
"match": {
"description": "{{query_string}}"
}
}
}
}
}Executing a search query using search template
GET /_search/template?pretty
{
"id": "search_template_1",
"params": {
"query_string": "hello world"
}
}The search request will be executed by default on all the indices available in the cluster and can be limited to particular indices using an index parameter.
Notes
- A dynamic index template is always useful when you do not know the field names in advance and want to control their mapping as per the business use case.
Log Context
Log “error adding legacy template [{}] for [{}]; request was not acknowledged” classname is IndexTemplateRegistry.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :
new ActionListener() { @Override public void onResponse(AcknowledgedResponse response) { creationCheck.set(false); if (response.isAcknowledged() == false) { logger.error("error adding legacy template [{}] for [{}]; request was not acknowledged"; templateName; getOrigin()); } } @Override
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