OpenSearchCon India 2026

Most teams have a dirty secret: they're running Elasticsearch versions they can't afford to upgrade and can't afford to stay on. The migration feels impossible due to data loss risk, query regression, extended downtime, and no rollback. So they wait. And wait. This talk ends the waiting. We walk through the OpenSearch Migration Assistant end-to-end: a fully open-source toolkit that handles metadata migration, historical backfill via Reindex-from-Snapshot, and live traffic capture + replay so your users never feel the move. We'll cover all three migration scenarios, the trickiest mapping transformation pitfalls (dense_vector → knn_vector, anyone?), and live comparative response diffing before the final cutover. Migrate smarter, not harder.