The move shows Amazon acting with a higher level of platform power as the world's businesses, schools and governments become more reliant on cloud providers, which now deliver basic computing and storage tools as well as higher-level services. As AWS is ahead of every other cloud provider, including Microsoft and Google , its moves in the open-source world can have an outsized impact on the companies that focus on distributing it.

Open-source search software company Elastic saw its stock fall as much as 5 percent on Tuesday after Amazon Web Services announced the launch of a separate library of open-source code for Elasticsearch, a set of technologies that can be use to build search engines for web sites, and an important part of Elastic's business.

Amazon and Elastic are tangled in a complicated dance of cooperation and competition, as is often the case with open-source technologies, which are free for anybody to modify, use and share. AWS has its own cloud service that draws on the Elasticsearch open-source technology. It competes with Elastic's own cloud-based service, which is available on AWS.

AWS executive Adrian Cockcroft explained Amazon's move to create a separate Elasticsearch code library in an extensive blog post on Monday. He wrote that AWS decided to act because it felt that Elastic's own repository of Elasticsearch code has become a blurry mixture of some code that has an open-source license, and some proprietary code.

"We have discussed our concerns with Elastic, the maintainers of Elasticsearch, including offering to dedicate significant resources to help support a community-driven, non-intermingled version of Elasticsearch. They have made it clear that they intend to continue on their current path," Cockcroft wrote. He noted that Expedia and Netflix, both large AWS customers, will be involved in the new community.

On Tuesday Elastic CEO Shay Banon shot back with a blog post of his own.

"Our products were forked, redistributed and rebundled so many times I lost count," Banon wrote. "It is a sign of success and the reach our products have. From various vendors, to large Chinese entities, to now, Amazon. There was always a 'reason,' at times masked with fake altruism or benevolence. None of these have lasted. They were built to serve their own needs, drive confusion, and splinter the community."

Paul Dix, co-founder and chief technology officer of open-source start-up InfluxData, described AWS' Elasticsearch move as "pulling out a gun at a knife fight."

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AWS has come out with open-source software in the past. Cockcroft pointed to Amazon Corretto, a free distribution of the OpenJDK software for working with the Java programming language. "Recently there was increased concern from our customers that Oracle would stop supporting the version of Java that customers relied upon, or change the licensing terms, and customers had good reason to be concerned," Cockcroft wrote.

But Oracle is older and much more established than Elastic -- which went public in October -- and generates revenue from areas other than Java, like database and application software.

AWS has also released other services that depend on open-source technologies backed by other companies, including MongoDB, although it has not created separate code libraries for them.