Elastic Search create index on startup

There are two ways to create an index on startup in Elasticsearch:

1. Use an index template: An index template is a prototype that defines the settings and mappings for an index. When Elasticsearch starts up, it will automatically create any indices that match the patterns defined in the index templates. To create an index template, you can use the PUT _index_template API.
2. Use a startup script: A startup script is a script that is executed when Elasticsearch starts up. You can use a startup script to create indices, perform other administrative tasks, or initialize your Elasticsearch cluster. To create a startup script, you can use the scripts directory in the Elasticsearch configuration directory.

Here is an example of an index template that you can use to create an index on startup:

JSON

{
  "index_patterns": ["my_index-*"],
  "settings": {
    "number_of_shards": 1,
    "number_of_replicas": 1
  },
  "mappings": {
    "properties": {
      "field1": {
        "type": "text"
      }
    }
  }
}

To create this index template, you would use the following command:

PUT _index_template/my_index
{
  "index_patterns": ["my_index-*"],
  "settings": {
    "number_of_shards": 1,
    "number_of_replicas": 1
  },
  "mappings": {
    "properties": {
      "field1": {
        "type": "text"
      }
    }
  }
}

Once you have created the index template, Elasticsearch will automatically create the my_index index when it starts up.

Here is an example of a startup script that you can use to create an index on startup:

Python

import elasticsearch

es = elasticsearch.Elasticsearch()

# Create the index
es.indices.create("my_index", settings={
  "number_of_shards": 1,
  "number_of_replicas": 1
})

# Add a mapping to the index
es.indices.put_mapping("my_index", {
  "mappings": {
    "properties": {
      "field1": {
        "type": "text"
      }
    }
  }
})

To create this startup script, you would save it as a .py file in the scripts directory in the Elasticsearch configuration directory. Then, you would configure Elasticsearch to run the startup script when it starts up. You can do this by setting the script.engine and script.inline settings in the Elasticsearch configuration file.

Once you have configured Elasticsearch to run the startup script, it will create the my_index index when it starts up.

Which method you choose to create an index on startup depends on your specific needs. If you need to create multiple indices with the same settings and mappings, then using an index template is a good option. If you need to create an index with custom settings and mappings, or if you need to perform other administrative tasks on startup, then using a startup script is a good option.