This article perpetuates the myth that Amazon forked Elasticsearch. They did not; not even close. The website they published links to a github organization that hosts a lot of repositories, all of which are plugins. They simply use the OSS builds that you can 1) produce with the official build scripts in Elasticsearch 2) That Elasticsearch actively publishes on their website in RPM and Docker form. The readme's for said plugins instruct you to download these! Sure, they make you look for it but still. The key premise that they don't do that is simply not true. And yes their repository contains clearly documented code that is a mix of several licenses. This is not confusing at all as it cannot be for legal reasons. The license file, which is very short, explains this.

What Amazon did do is replicate some of the functionality Elastic has in their proprietary code base in the form of plugins and open sourced that. Very nice of them and completely fine of course. But I'd like to point out that they are not very actively contributing to Elasticsearch directly and fully dependent on Elastic (and others) continuing to do the R&D for them. Elastic meanwhile continues to distribute the core of their product under the very permissive Apache 2.0 license, which allows Amazon to do this and which Elastic is fully committed to continuing to use. Meanwhile they ship a lot of their added value as non OSS software, which means their business is not that much threatened by the mediocre ripoff by Amazon. Some of that is actually freely usable; some of that indeed requires a commercial license. Likewise, Amazon ships OSS (like Elastic) and proprietary stuff but makes their money from hosting stuff rather than licensing it. Elastic does the same with Elastic cloud.

In doing so, they are going against the trend at e.g. MongoDB of using a very restrictive OSS license that pretty much requires a commercial license in most corporate environments and is also problematic for commercial partners to contribute to. Apache 2.0 is a license of choice for mutually competing companies to collaborate and indeed Elastic is part of a wider ecosystem in the Apache foundation with stuff like Lucene, Solr, academics, and many similar companies actively contributing and collaborating to the same projects and libraries that they all depend on. I've always regarded this as very productive environment and Elastic as a successful player is IMHO a positive thing.

I don't judge what Amazon did here other than taking offense at them taking the moral high ground in situation where arguably all they are doing is packaging up something that Elastic did, as is (again, not a fork) without contributing much more than the meager selection of plugins they mostly got from elsewhere to sort of provide a bare-bones experience for starting users. I'd strongly recommend not using them for technical reasons because you can and will experience major issues for which Amazon support won't be great. If you have a throwaway environment that you can afford to lose, its fine. Meanwhile, I'd say gratitude rather than arrogance would be more appropriate for Amazon. I think it's primarily their attitude that triggered the response by Shay Banon.