A detailed comparison of OpenSearch and Elasticsearch covering licensing, features, security, plugins, visualization tools, compatibility, community support, and guidance on choosing between them.
Introduction
OpenSearch and Elasticsearch are powerful, open-source search and analytics engines used for log analytics, full-text search, and real-time data analysis. This article provides a thorough comparison to help teams decide which engine best fits their needs.
Elasticsearch
Elasticsearch is a distributed, RESTful search and analytics engine developed by Elastic NV. Built on top of Apache Lucene, it forms the core of the Elastic Stack (also known as ELK), which includes Kibana, Logstash, and Beats. Elasticsearch has a long track record and a large ecosystem of integrations and commercial features.
OpenSearch
OpenSearch is a community-driven, open-source search and analytics suite derived from Elasticsearch and Kibana. It was initiated by Amazon Web Services (AWS) after Elastic changed the licenses for Elasticsearch and Kibana from Apache 2.0 to SSPL and the Elastic License.
Licensing
Elasticsearch
Starting with version 7.11, Elasticsearch is distributed under the Elastic License or SSPL, neither of which is OSI-approved. This affects how organizations can use, modify, and distribute the software, particularly for managed service providers.
OpenSearch
OpenSearch is released under the Apache 2.0 license, an OSI-approved open-source license. This guarantees that it remains free to use, modify, and distribute for any purpose.
Features Comparison
Core Functionality
Both engines provide:
- Full-text search with advanced query DSL
- Distributed architecture with automatic sharding and replication
- RESTful APIs for indexing and querying
- Aggregation framework for analytics
- Near real-time search capabilities
Plugins & Extensions
Elasticsearch bundles proprietary plugins (X-Pack) for security, alerting, monitoring, and machine learning under a commercial license.
OpenSearch offers open-source alternatives:
- Security plugin -- Role-based access control, encryption, audit logging
- Alerting plugin -- Configurable alerts based on data conditions
- Anomaly Detection -- Machine learning-powered anomaly detection
- SQL plugin -- Query data using SQL syntax
- Index Management -- Automated index lifecycle policies
Compatibility
Elasticsearch: Newer releases may introduce breaking API changes. Open-source builds ceased at version 7.10.
OpenSearch: Forked from Elasticsearch 7.10.2, OpenSearch maintains API compatibility for the time being, though divergence is expected over time as both projects evolve independently.
Community & Support
Elasticsearch is backed by Elastic NV with official commercial support and training. Community contributions flow through a more controlled process.
OpenSearch is community-driven with AWS leadership. The project is fully open to external contributions, and governance is more transparent.
Performance & Scalability
Both engines are built for high-throughput, distributed workloads. Since OpenSearch forked from Elasticsearch 7.10.2, initial benchmarks show similar performance characteristics. Future optimizations may cause the two to diverge.
Security
Elasticsearch provides advanced security features through X-Pack, which requires a commercial license for full functionality.
OpenSearch includes a built-in security plugin under the Apache 2.0 license, offering TLS encryption, authentication, role-based access control, and audit logging at no additional cost.
Visualization Tools
Kibana (Elasticsearch)
Kibana provides dashboards, visualizations, and data exploration tools. From version 7.11 onward, it is distributed under the Elastic License / SSPL.
OpenSearch Dashboards
OpenSearch Dashboards is forked from Kibana 7.10.2 and is fully Apache 2.0 licensed. It provides a similar visualization experience with an open-source guarantee.
Use Cases
- Choose Elasticsearch when the team needs specific commercial features from the Elastic Stack, prefers Elastic's managed cloud offering, or requires advanced ML capabilities built into the platform.
- Choose OpenSearch when open-source licensing is a hard requirement, when running on AWS and wanting native integration, or when avoiding vendor lock-in is a priority.
Pros & Cons Summary
Elasticsearch Pros
- Mature ecosystem with extensive documentation
- Advanced ML and security features via X-Pack
- Strong commercial support from Elastic NV
Elasticsearch Cons
- Restrictive licensing from version 7.11 onward
- Commercial features require paid subscriptions
- Managed service restrictions under SSPL
OpenSearch Pros
- Truly open-source under Apache 2.0
- Built-in security and alerting at no cost
- Active community with AWS backing
- No licensing restrictions for managed services
OpenSearch Cons
- Smaller ecosystem compared to Elastic Stack
- May lag behind Elasticsearch in some advanced features
- Long-term API divergence from Elasticsearch
Final Thoughts
Both OpenSearch and Elasticsearch excel at search and analytics workloads. OpenSearch guarantees open-source freedom and includes security features at no cost, while Elasticsearch provides a deeper set of commercial features under more restrictive licensing. We recommend choosing based on the project's specific feature requirements, licensing constraints, and support needs.
Frequently asked questions
What is the main difference between OpenSearch and Elasticsearch?
OpenSearch is released under Apache 2.0, an OSI-approved open-source license, while Elasticsearch moved at version 7.11 to the Elastic License or SSPL, neither of which is OSI-approved. Elasticsearch offers a deeper set of commercial features, and OpenSearch includes security at no cost. Core search features overlap heavily because OpenSearch was forked from Elasticsearch 7.10.2.
Why did AWS create OpenSearch?
AWS started OpenSearch after Elastic changed the licenses for Elasticsearch and Kibana from Apache 2.0 to SSPL and the Elastic License. OpenSearch is a community-driven fork of Elasticsearch and Kibana that stays under Apache 2.0, is fully open to external contributions and has more transparent governance.
Is OpenSearch API-compatible with Elasticsearch?
OpenSearch forked from Elasticsearch 7.10.2 and maintains API compatibility for the time being. Divergence is expected as the two projects evolve independently, and newer Elasticsearch releases may introduce breaking API changes. Initial benchmarks show similar performance for the same reason, though future optimizations may pull them apart.
Is security free in OpenSearch?
Yes. OpenSearch includes a built-in security plugin under the Apache 2.0 license, with TLS encryption, authentication, role-based access control and audit logging at no additional cost. Elasticsearch delivers its advanced security features through X-Pack, which needs a commercial license for full functionality.
What replaces Kibana in OpenSearch?
OpenSearch Dashboards is the counterpart to Kibana. It was forked from Kibana 7.10.2, is fully Apache 2.0 licensed and offers a similar experience for dashboards, visualizations and data exploration. Kibana itself has been distributed under the Elastic License or SSPL from version 7.11 onward.
Which OpenSearch plugins replace Elasticsearch X-Pack features?
X-Pack bundles security, alerting, monitoring and machine learning for Elasticsearch under a commercial license. OpenSearch offers open-source alternatives, including a security plugin with role-based access control and audit logging, an alerting plugin, machine learning-powered anomaly detection, a SQL plugin for querying with SQL syntax, and index management with automated lifecycle policies.
When should I choose Elasticsearch instead of OpenSearch?
Elasticsearch fits when a team needs specific commercial Elastic Stack features, prefers Elastic's managed cloud offering or wants advanced ML capabilities built into the platform. Its mature ecosystem, extensive documentation and commercial support from Elastic NV count in its favor too. OpenSearch suits teams for whom open-source licensing is a hard requirement, who run on AWS and want native integration, or who want to avoid vendor lock-in.
Does the SSPL license restrict offering Elasticsearch as a managed service?
Managed service providers feel the licensing change most. The Elastic License and SSPL that Elasticsearch adopted from version 7.11 affect how the software can be used, modified and distributed, and SSPL places restrictions on managed services. OpenSearch, released under Apache 2.0, has no licensing restrictions for managed services.
Read how we handle it in Cloud & Server Management.
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