Running an open source project is a lot of work. There needs to be a model how to sustain this work for the project to be successful. This can be a business model, a way to raise funding without running a business, a model of channeling volunteer work, or some combination of different models.
The following stepping stones form the path of sustainability. They are not in a specific order. Each project will pick and arrange them in a way that is suitable to them.
There are a variety of business models which include creating open source software and funding its development.
- Various dual licensing, open core, etc. models
- Products based on open source
- Support and services
A working business model can fund development of an open source project, while in turn the open source project and community and adoption of the project can act as leverage within the business model to sustain and grow business as well as community.
Most open source software, especially software that is not in the focus of commercial usage, is produced at least partly by volunteers.
Provide a model which supports volunteer work, which balances volunteer work and work done by people who get paid for it, strive for making opportunities inclusive.
Quite some projects get significant donations. These can be donations to individual developers or to organizations supporting one or more projects. They can come from individuals or from companies. They can come spontaneously, by dedicated sponsorship programs, or through things like crowd-funding campaigns.
Build the blocks which fit to your project.
And don't sell free software cheap.
Some companies give their some time to do things which are not directly part of their daily work (20% time, hack week, etc.). Some companies also hire people to work on open source projects without direction of the company so that they can fully work in the interest of the open source project. All this is very dependent on project, company, individuals, but can be a very valuable resource.
Open source projects can strive to make it easy for such arrangements to work so that they can benefit from this very valuable resource. A lot of that is covered by other stepping stones such as responsiveness, predictability etc.