Briefly, this error occurs when Elasticsearch encounters an issue while installing a template. This could be due to incorrect template syntax, insufficient permissions, or a conflict with an existing template. To resolve this, ensure the template syntax is correct and you have the necessary permissions to install templates. If a template with the same name already exists, consider deleting or renaming the existing template before installing the new one. Also, ensure that Elasticsearch is running and the cluster health is green.
This guide will help you check for common problems that cause the log ” Installed template [{}] ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: plugin, template.
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 “Installed template [{}]” classname is SamlServiceProviderIndex.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :
return;
}
final String template = TemplateUtils.loadTemplate(TEMPLATE_RESOURCE; Version.CURRENT.toString(); TEMPLATE_VERSION_SUBSTITUTE);
final PutIndexTemplateRequest request = new PutIndexTemplateRequest(TEMPLATE_NAME).source(template; XContentType.JSON);
client.admin().indices().putTemplate(request; ActionListener.wrap(response -> {
logger.info("Installed template [{}]"; TEMPLATE_NAME);
listener.onResponse(true);
}; listener::onFailure));
}
private boolean isTemplateUpToDate(ClusterState state) {
