Earlier this month, Elastic announced that there would be upcoming changes to its open source licensing. These changes do not affect on-prem deployments of Elasticsearch. Since Mattermost Enterprise Edition uses Elasticsearch in its on-prem deployments, we felt it important to explore the reasoning behind Elastic’s decision, how the new license terms are different, and why there will be no impact on Mattermost users as a result of these changes.
What is Elasticsearch?
Elasticsearch is a distributed search engine that was originally developed and licensed primarily under the Apache 2.0 open source license. Elasticsearch was founded by Shay Banon and evolved out of his earlier project, Compass, which he began back in 2005.
Why did Elastic change its licensing terms?
If you read Banon’s announcement blog from earlier this month, he essentially declared that the impetus for changing Elasticsearch’s licensing model stemmed from his frustration with cloud providers—namely Amazon.
Beginning with their 7.11 release, Elasticsearch will move from being licensed under the Apache License, version 2.0 license to a dual Server Side Public License and Elastic License. Banon has spent many years dedicating his time to building quality products that contribute to the open source community. He finally had enough of Amazon taking advantage of open source tools by making a profit off of the efforts of others without giving back to the community, and so he decided to take a stand.
What does the new license change?
For users, Elasticsearch will continue to be licensed under the terms of the Elastic License, and there will be no changes. The main change is focused towards those who sell Elasticsearch as a service, such as Amazon Elasticsearch Service.
As a result of this change in licenses, Elasticsearch will no longer be considered open source, and instead will be “Free & Open” since neither the Server Side Public License (“SSPL”) nor the Elastic License have been approved by the Open Source Initiative. As a copyleft license, the SSPL requires that—when providing a product as a service under this license—any modifications as well as source code of the management layers must be publicly released under the same SSPL license.
How is Elasticsearch used within the Mattermost Enterprise Edition installation?
Mattermost Enterprise Edition does not actually use the Elasticsearch source code in its self-hosted implementation. Instead, users are instructed to set up their own Elasticsearch server. Then as part of the implementation, the user’s Elasticsearch server is configured with the Mattermost installation using a third-party library.
More information on the Mattermost Elasticsearch implementation can be found in the deployment documentation.
How does this new licensing structure impact Mattermost Enterprise Edition users?
There should be no direct impact on the use of Mattermost Enterprise Edition due to this change from a licensing perspective. It is clear from Elastic’s FAQs that the change will not be impacting users of the Elasticsearch product, only cloud providers using it to provide cloud services.
However, users deploying their installation in the cloud will need to consider whether or not their cloud providers are or may be impacted. For now, the move mostly seems to be directed against Amazon and AWS services. Elastic AWS Open Source announced in a responsive blog post that since Elastic will no longer be offering an open source version of Elasticsearch, AWS Open Source plans on forking the open source version and maintaining it under the Apache License, Version 2.0. It is unknown at this time what amount of efforts will be required to maintain compatibility with both versions of Elasticsearch.
At Mattermost, we plan to continue to integrate with Elasticsearch for our self-hosted product even after their licensing change, since it doesn’t materially impact our users.
If you’re interested in deploying Mattermost itself, you can download our open source server product as a single Linux binary under MIT license for on-prem messaging collaboration across PC, web and mobile with unlimited integration, continuous archiving and instant search.