Open Source Business Models
At this point, it is worth considering exactly how open source projects are funded. How do companies hope to make money off an open source database product?
Companies such as Datastax, which markets Cassandra software, and MongoDB can make money from an open source database product in a number of ways:
- They may offer support services around an open source product that is otherwise freely available.
- They may offer commercial extensions to an open source product. For instance, both Datastax and MongoDB offer “enterprise” versions of their respective database platforms. These enterprise versions typically comprise closed source extensions that help manage or develop applications around an open “core.”
- They can offer a fully managed, hosted version of the software product—?a database-as-a-service offering.
Historically, the first two options have been difficult. If the open source product is useful enough to garner rapid adoption, then it is often so usable that support services are not necessary and the enterprise version is superfluous. Finding the right balance between a fully functional core product while still leaving a gap that creates a need for support and enterprise versions has been a difficult balance to achieve.
The third business model option—offering a fully managed cloud database—has turned out to be far more successful. Enterprises can easily justify the cost of the fully managed service from the reduction in operational costs of running the database on-premise, and the vendor can amortize the expense of managing the platform across many customers. It’s a win-win for both the vendor and the consumer.
New Licensing Approaches
That’s why some of the open source database vendors were so alarmed at the threat from Amazon. Fully managed cloud offerings beckoned as the ideal way to monetize the investment in open source. But Amazon seemed on the verge of undercutting the vendors by offering open source databases in their cloud.
In response, companies such as MongoDB, Redis, and Elastic moved away from the pure open source licenses that permitted such exploitation. A prime example is MongoDB’s Server Side Public License (SSPL). The SSPL allows for most of the activities of the AGPL license under which MongoDB was previously licensed but forbids offering the product as a cloud service. Cloud vendors are, of course, able to license MongoDB from the MongoDB company—just as they license Oracle and other commercial databases, but they are effectively prevented from using the community edition license for this purpose.
The Elastic company offers Elasticsearch under its own Elastic License as well as the SSPL. Redis still offers its core engine under a BSD license, but licenses add-on modules under the Redis Source Available License (RSAL).
The Open Source Initiative (OSI) has made it clear that the SSPL—and other similar licenses—does not meet its definition of open source. Consequently, it’s strictly correct to say that these databases are no longer open source. Some people are now calling these licenses “source available.”
Philosophical Differences
Critics of the SSPL and other similar licenses believe that, in the long run, backing away from open source is not in the best interests of the project, or even of the company, concerned. For instance, with a restrictive license such as the SSPL, an enterprise may feel “locked-in” to the database vendor since no one else but that vendor can economically offer the product as a cloud service.
Furthermore, in practice, while the SSPL and similar licenses prevent the use of the database product itself, they do not stop cloud vendors from offering look-alike “clones” of the product. Both Microsoft and Amazon offer services that support the MongoDB and Cassandra APIs but do not incorporate any of the MongoDB or Cassandra code base.
In contrast, the not-quite-open-source-?anymore database vendors believe that they are simply protecting their ability to innovate and thrive in the cloud era. If a competitor can offer an equivalent cloud product without having to invest in research and development, then it has a competitive advantage. Companies such as Amazon could therefore squeeze all the value from existing open source databases and force the companies that are investing in these technologies out of the market. In the long run, this might damage or even destroy the open source projects.
Companies such as MongoDB will also point out that, for the vast majority of users, all the benefits of the previous open source licenses still exist. The only disadvantaged parties are the mega-cloud vendors.
At the core of this polite civil war is a philosophical difference about the role and importance of open source. Some companies and professionals believe that open source is more than just a means to accelerate specific technologies—it’s a way to democratize innovation and improve society. For instance, Percona supports and promotes multiple open source database platforms and is committed to ensuring that all of the benefits of open source are available to all. For Percona, open source is at the core of its business and beliefs. However, for a company such as MongoDB, the core of the business is database software—how it is licensed is secondary to adoption rates and revenue generation.
Looking Ahead at Open Source Databases
The split between truly open source databases, such as Cassandra, Postgres, and MariaDB, and the “available source” databases—MongoDB, Redis, and Elastic—seems unlikely to reverse. Going forward, it looks as if new, emerging database platforms will be divided between the two licensing models. The up-and-coming CockroachDB system is licensed under the Business Source License (BSL) that prevents anyone from offering the database as a service, while the very similar Yugabyte system is licensed under the truly open source Apache license.
The one thing that seems certain is that closed source licenses are not the way of the future. The advantages of free and open source software in terms of user adoption and competitiveness are simply too great. And while there’s no doubt that Amazon profits mightily from the exploitation of open source projects, these projects remain healthy, and we can anticipate that open and available source projects will power the next wave of database innovation.