Index templates in Elasticsearch - Mini Project: Build & Apply

Create and Use an Elasticsearch Index Template

📖 Scenario: You are managing a logging system that stores logs from multiple applications. To keep the data organized and consistent, you want to create an index template in Elasticsearch. This template will automatically apply settings and mappings to new log indexes that match a specific pattern.

🎯 Goal: Build an Elasticsearch index template named log_template that applies to indexes starting with logs-. The template should set the number of shards to 1 and define a mapping for a timestamp field as a date type.

📋 What You'll Learn

Create an index template named log_template

Set the index pattern to logs-*

Configure the template to set number_of_shards to 1

Add a mapping for the timestamp field with type date

💡 Why This Matters

🌍 Real World

Index templates help automate consistent settings and mappings for new indexes, saving time and avoiding errors in large logging or data systems.

💼 Career

Understanding index templates is essential for roles like DevOps, data engineers, and backend developers working with Elasticsearch to manage scalable search and analytics systems.

1

Create the basic index template structure

Create an index template named log_template with an empty index_patterns list and empty template object.

Elasticsearch

{
  "index_patterns": [],
  "template": {}
  # Your code here
}

Need a hint?

Use "index_patterns": ["logs-*"] to match indexes starting with logs-.

2

Add index settings for shards

Inside the template object, add settings with number_of_shards set to 1.

Elasticsearch

{
  "index_patterns": ["logs-*"] ,
  "template": {
    "settings": {
      # Your code here
    }
  }
}

Need a hint?

Put "number_of_shards": 1 inside settings.

3

Add mapping for the timestamp field

Inside the template object, add a mappings object with a properties field. Define timestamp as a date type.

Elasticsearch

{
  "index_patterns": ["logs-*"] ,
  "template": {
    "settings": {
      "number_of_shards": 1
    },
    "mappings": {
      "properties": {
        # Your code here
      }
    }
  }
}

Need a hint?

Define timestamp inside properties with "type": "date".

4

Complete the index template JSON

Ensure the full JSON includes index_patterns, template with settings and mappings as specified. This is the final complete index template.

Elasticsearch

{
  "index_patterns": ["logs-*"] ,
  "template": {
    "settings": {
      "number_of_shards": 1
    },
    "mappings": {
      "properties": {
        "timestamp": {
          "type": "date"
        }
      }
    }
  }
}
# Your code here to complete the template if needed

Need a hint?

Review the entire JSON to confirm all parts are included and correctly formatted.