How to reindex in OpenSearch?

Reindexing creates a new version of an index with different settings or mappings, or copies documents from one index to another. On Logit.io you can run a reindex from OpenSearch Dashboards Dev Tools or programmatically via the OpenSearch REST API.

Prerequisites

• Active Logit.io account (opens in a new tab) with a Logs stack.
• Familiarity with OpenSearch Dashboards or your stack's OpenSearch API credentials from Settings → Endpoints (Connect to Your Cluster).
• Basic understanding of JSON and OpenSearch Query DSL.

Option 1: Reindex using OpenSearch Dashboards Dev Tools

Step 1: Open Dev Tools

1. Sign in to your Logit.io account.
2. Open Launch Logs to open OpenSearch Dashboards.
3. In the left menu, select Dev Tools.

Step 2: Plan your reindex

Decide on:

• Source index — the index (or indexes) to copy from
• Destination index — the target index (created automatically if it does not exist)
• Script (optional) — transformations to apply during reindexing

Step 3: Run the reindex command

In the Dev Tools console:

POST /_reindex
{
  "source": {
    "index": "source_index_name"
  },
  "dest": {
    "index": "destination_index_name"
  }
}

Replace source_index_name and destination_index_name with your index names.

Step 4: Monitor and verify

Reindex duration depends on index size and any scripts used. Monitor progress in OpenSearch Dashboards.

After completion, verify document count in the destination index:

GET /destination_index_name/_count

Compare the result with the source index count.

Option 2: Reindex using the OpenSearch REST API

Use the same POST /_reindex request against your stack endpoint. Copy credentials from Settings → Endpoints.

Basic authentication:

curl -X POST "@elasticsearch.endpointAddress:443/_reindex" \
  -u "@elasticsearch.username:@elasticsearch.password" \
  -H "Content-Type: application/json" \
  -d '{
    "source": { "index": "source_index_name" },
    "dest": { "index": "destination_index_name" }
  }'

API key authentication:

curl -X POST "@elasticsearch.endpointAddress:443/_reindex?apikey=@elasticsearch.apiKey" \
  -H "Content-Type: application/json" \
  -d '{
    "source": { "index": "source_index_name" },
    "dest": { "index": "destination_index_name" }
  }'

Check the destination index count:

curl -X GET "@elasticsearch.endpointAddress:443/destination_index_name/_count?pretty" \
  -u "@elasticsearch.username:@elasticsearch.password"

Troubleshooting

Failed reindexing — Check the response body for errors. Common causes include script errors, mapping conflicts, or insufficient cluster resources.

Performance — Large reindexes can affect cluster performance. Run them during quieter periods where possible.

For complex reindex jobs or persistent errors, contact the Logit.io support team (opens in a new tab).