Elasticsearch and the OpenSearch Fork¶

Year: 2021

Lesson: License changes spawn forks, and forks can succeed

What Happened¶

Elastic, the company behind Elasticsearch and Kibana, changed their license.¹ These tools had been Apache 2.0—about as permissive as it gets. Suddenly they were dual-licensed under SSPL and the Elastic License 2.0.

Neither is open source. The Apache-licensed Elasticsearch was gone.

2024 Update

In August 2024, Elastic added AGPL v3 as a third licensing option for Elasticsearch and Kibana.³ Elasticsearch is technically open source again — but under a very different license than the Apache 2.0 it started with. Whether this rebuilds community trust is another question entirely.

Their stated reason: Amazon. AWS offered Elasticsearch as a managed service and had even created their own distribution called "Open Distro for Elasticsearch." Elastic felt AWS was benefiting from their work without contributing back.

Amazon's Response¶

AWS did something unexpected: they forked.

Within weeks of Elastic's announcement, AWS launched OpenSearch—a fork of the last Apache-licensed Elasticsearch and Kibana.² They committed to maintaining it under Apache 2.0 and created the OpenSearch project with independent governance.

This wasn't just a corporate fork. AWS invested in community building, accepted external contributions, and positioned OpenSearch as the community continuation of what Elasticsearch used to be.

The timeline where AWS becomes the open source hero was not on my bingo card.

The Fallout¶

Two competing projects¶

The search engine market now has:

Elasticsearch — Elastic's product, now tri-licensed under SSPL, Elastic License 2.0, and AGPL v3
OpenSearch — AWS-backed fork, under Apache 2.0, now a Linux Foundation project with 1,400+ contributors

Both are actively developed. Both have users. The community split.

Cloud provider detente¶

Other cloud providers (like AWS) can offer OpenSearch. They cannot offer Elasticsearch without licensing agreements.

This was exactly Elastic's goal—but the cost was fragmenting the ecosystem.

Community trust¶

Elastic had positioned themselves as open source champions for years. The relicensing felt like a betrayal to many users. The AWS fork gave those users somewhere to go.

The Ironies¶

AWS as open source defender¶

Amazon Web Services—frequently criticized for profiting from open source without contributing—became the defender of open source licensing in this story. They forked to preserve Apache 2.0, funded ongoing development, and built community governance.

The company that many saw as the problem became, in this instance, part of the solution.

The trademark fight¶

Elastic owned the "Elasticsearch" trademark. AWS couldn't use it. Hence "OpenSearch"—a rebrand for a fork. Trademarks, not copyright, determined what the fork could be called.

Elastic came back — sort of¶

Elastic didn't collapse. Their stock recovered. Their business model shifted but survived. And then in 2024, they added AGPL as a licensing option — making Elasticsearch open source again, three years after closing it.

But the damage was done. OpenSearch had matured under the Linux Foundation with independent governance and a growing contributor base. Developers who migrated aren't rushing back.⁴ It turns out you can re-open the source, but you can't un-fork the community.

The Lessons¶

Forks are real threats¶

Before this, many assumed that forking a major project was impractical—too much engineering effort, too little community interest. OpenSearch proved otherwise. With sufficient resources and motivation, forks can succeed.

Trademarks matter¶

Elastic controlled "Elasticsearch." AWS had to rebrand. If you're building an open source project, your trademark is separate from your copyright and license. Protect it.

Community governance prevents this¶

Single-company projects can relicense at will. Foundation-governed projects (Apache, Linux, Mozilla) cannot—the contribution agreements don't permit it. If you're choosing a dependency, governance structure is a risk factor.

Relicensing can be reversed — but forks can't¶

Elastic proved that closing source is reversible. Adding AGPL gave Elasticsearch an open source license again. But the fork was irreversible. OpenSearch exists, has momentum, and has independent governance. The community split is permanent even if the licensing issue isn't.

The cloud wars reshape open source¶

This wasn't really about licensing philosophy. It was about business competition between Elastic and AWS. Open source licensing became a battleground for corporate strategy.

What This Means For You¶

When adopting infrastructure software:

Check the license AND the governance
Single-company projects can change licenses
Foundation projects have stronger guarantees
Have a contingency plan (could you switch to a fork?)

When building open source:

Decide early whether you want single-company control or community governance
Understand that permissive licensing means cloud providers can compete with you
If that's unacceptable, consider your licensing carefully from the start—changing later has costs