Question 1

Should I migrate from Elasticsearch to OpenSearch?

Accepted Answer

Migrate if: (a) your distribution model conflicts with SSPL or ELv2, (b) you're on AWS and Amazon OpenSearch Service is meaningfully cheaper than Elastic Cloud on AWS, (c) you don't depend on Elastic-Inc.-only features (ESQL, Universal Profiling, advanced ML jobs, observability auto-instrumentation). Stay on Elasticsearch if: (a) you depend on those proprietary features, (b) you have an Elastic Cloud contract with the SLA you want, (c) you use the newer ELSER sparse embedding for hybrid search — ELSER is Elastic-only.

Question 2

Is OpenSearch a true drop-in replacement for Elasticsearch?

Accepted Answer

Up to Elasticsearch 7.10 (where the fork happened), yes — wire-protocol and query DSL are identical. Beyond that, OpenSearch has its own independent roadmap. Field types, aggregation behaviour, and security plugin semantics have diverged since 2021. Migrating an Elasticsearch 8.x cluster to current OpenSearch needs a real validation pass — query DSL, dashboards (Kibana to OpenSearch Dashboards conversion), and index template review.

Question 3

What about vector search and RAG?

Accepted Answer

Both engines now support vector search. Elasticsearch added kNN with HNSW (8.0+) and ELSER sparse-vector retrieval for hybrid search. OpenSearch has its k-NN plugin with multiple algorithms (HNSW, IVF) and the Neural Search plugin for end-to-end embedding pipelines. For RAG workloads: Elasticsearch's ELSER is unique and stronger for English-text recall; OpenSearch's open Neural Search lets you bring your own embedding model end-to-end without licensing constraints. Pick based on the embedding model you intend to use.

Question 4

Kibana vs OpenSearch Dashboards — how different are they?

Accepted Answer

OpenSearch Dashboards is a fork of Kibana 7.10. UI muscle-memory transfers cleanly. The divergence is in: Elastic-proprietary apps (APM, Synthetics, Observability suite, ESQL editor) — these don't exist in OpenSearch Dashboards. OpenSearch has Trace Analytics, Anomaly Detection, and Index Management as native equivalents. For pure visualisation + Discover usage, they're interchangeable. For observability with Elastic's integrations, Kibana is still ahead.

Question 5

Elastic Cloud vs Amazon OpenSearch Service — which managed?

Accepted Answer

Elastic Cloud runs on AWS, Azure, GCP — single vendor across clouds, latest Elasticsearch features first, Elastic's commercial SLA. Amazon OpenSearch Service is AWS-only, deeply integrated with IAM/VPC/KMS, and is the cheaper option for AWS-resident workloads at scale. The decision is: do you want vendor-vs-cloud-provider relationship, single-cloud lock-in, and the AWS-native cost model? Or do you want feature-leadership and multi-cloud portability? We model the workload before recommending.

Question 6

What about the security plugin (X-Pack Security vs OpenSearch Security)?

Accepted Answer

Elasticsearch X-Pack Security (now bundled in the basic tier) provides role-based access, document/field-level security, IP filtering, and audit. OpenSearch Security (forked from Search Guard) provides equivalent role-based access, document/field-level security, multi-tenancy, and audit — but the configuration model differs. Migrating role mappings and audit configs is the largest single piece of work in an ES → OS migration; budget time for it.

Dimension	Elasticsearch 8.x	OpenSearch 2.x
Licence	SSPL / ELv2 dual-licence (post-7.11 fork)	Apache 2.0 — permissive, OSI-approved
Steward	Elastic NV (commercial vendor)	OpenSearch Software Foundation (Linux Foundation-hosted)
Dashboards	Kibana (Elastic-proprietary apps included)	OpenSearch Dashboards (Kibana 7.10 fork, native equivalents)
Vector / kNN search	Dense vectors (HNSW) + ELSER sparse vectors (Elastic-only)	k-NN plugin (HNSW, IVF) + Neural Search end-to-end pipeline
Query language	Query DSL + ESQL (Elastic-proprietary SQL-like)	Query DSL + SQL (open) + PPL (Piped Processing Language)
Observability	APM, Synthetics, Universal Profiling, Logs+Metrics+Traces native	Trace Analytics + integration with Data Prepper + OpenTelemetry
Machine learning	Anomaly Detection, Forecasting, NLP inference (Elastic-licensed)	Anomaly Detection (open) + ML Commons for model serving
Security	X-Pack Security (RBAC, doc/field-level, audit) — bundled basic tier	OpenSearch Security (forked from Search Guard) — equivalent, open
Cloud-managed	Elastic Cloud (AWS / Azure / GCP)	Amazon OpenSearch Service (AWS only), Aiven, others
Hot-warm-cold tiering	ILM (Index Lifecycle Management) with searchable snapshots	ISM (Index State Management) with searchable snapshots
Release cadence	Faster — Elastic ships latest features first (vector, ESQL, ML)	Slower but predictable — community + AWS-driven roadmap

Elasticsearch vs OpenSearch

Feature matrix

When Elasticsearch wins

When OpenSearch wins

Migration paths between Elasticsearch and OpenSearch

Elasticsearch 7.10 → OpenSearch

Elasticsearch 8.x → OpenSearch 2.x

Self-managed ES → Amazon OpenSearch Service

Common questions

Need a written ES-vs-OS decision?