Template priority and composition in Elasticsearch - Mini Project: Build & Apply

Template Priority and Composition in Elasticsearch

📖 Scenario: You are managing an Elasticsearch cluster that uses index templates to define settings and mappings for new indexes. You want to learn how to create multiple templates with different priorities and how Elasticsearch composes them when creating an index.

🎯 Goal: Build multiple index templates with different priorities and overlapping index patterns. Learn how Elasticsearch merges these templates based on priority and composition rules.

📋 What You'll Learn

Create two index templates with overlapping index patterns

Assign different priorities to each template

Use template composition with composed_of to reuse component templates

Create a new index that matches the templates

Observe the final merged settings and mappings applied to the index

💡 Why This Matters

🌍 Real World

Index templates help manage settings and mappings for many indexes automatically, saving time and avoiding errors.

💼 Career

Understanding template priority and composition is important for Elasticsearch administrators and developers managing scalable search systems.

1

Create a component template called base_settings

Create a component template called base_settings with the following settings: number_of_shards set to 1 and number_of_replicas set to 1.

Elasticsearch

# Create component template base_settings with number_of_shards=1 and number_of_replicas=1
# Your code here

Need a hint?

Use the PUT _component_template/base_settings API with a JSON body containing settings for shards and replicas.

2

Create two index templates with different priorities and composition

Create two index templates: template_low with priority 10 and template_high with priority 20. Both templates should apply to index pattern logs-*. template_low should compose the base_settings component template and add a mapping for a message field of type text. template_high should add a mapping for a user field of type keyword.

Elasticsearch

PUT _component_template/base_settings
{
  "template": {
    "settings": {
      "number_of_shards": "1",
      "number_of_replicas": "1"
    }
  }
}

# Create template_low with priority 10, compose base_settings, add message mapping
# Create template_high with priority 20, add user mapping
# Your code here

Need a hint?

Use PUT _index_template/ API to create each template. Use priority and composed_of fields as described.

3

Create an index that matches the templates

Create a new index called logs-2024-06 that matches the index pattern logs-* to apply the templates.

Elasticsearch

PUT _component_template/base_settings
{
  "template": {
    "settings": {
      "number_of_shards": "1",
      "number_of_replicas": "1"
    }
  }
}

PUT _index_template/template_low
{
  "index_patterns": ["logs-*"] ,
  "priority": 10,
  "composed_of": ["base_settings"],
  "template": {
    "mappings": {
      "properties": {
        "message": { "type": "text" }
      }
    }
  }
}

PUT _index_template/template_high
{
  "index_patterns": ["logs-*"] ,
  "priority": 20,
  "template": {
    "mappings": {
      "properties": {
        "user": { "type": "keyword" }
      }
    }
  }
}

# Create the index logs-2024-06
# Your code here

Need a hint?

Use the PUT API with the index name logs-2024-06 to create the index.

4

Check the final merged mappings and settings of the index

Use the GET logs-2024-06/_mapping and GET logs-2024-06/_settings APIs to print the final mappings and settings applied to the logs-2024-06 index.

Elasticsearch

PUT _component_template/base_settings
{
  "template": {
    "settings": {
      "number_of_shards": "1",
      "number_of_replicas": "1"
    }
  }
}

PUT _index_template/template_low
{
  "index_patterns": ["logs-*"] ,
  "priority": 10,
  "composed_of": ["base_settings"],
  "template": {
    "mappings": {
      "properties": {
        "message": { "type": "text" }
      }
    }
  }
}

PUT _index_template/template_high
{
  "index_patterns": ["logs-*"] ,
  "priority": 20,
  "template": {
    "mappings": {
      "properties": {
        "user": { "type": "keyword" }
      }
    }
  }
}

PUT logs-2024-06

# Get and print the mappings and settings of logs-2024-06
# Your code here

Need a hint?

Use GET logs-2024-06/_mapping and GET logs-2024-06/_settings to see the final applied templates.