Drupal distributions, or distros, are versions of Drupal that have been pre-configured to do a particular thing. They are, in some ways, new software that uses Drupal as a component. Some distros, like Commerce Kickstart for launching e-commerce sites, are used by tens of thousands of sites that share a common need. There are also distros designed by and for higher education, like Harvard’s OpenScholar, which powers faculty websites along with providing a simple web-based publishing platform for academics.

Drupal distros may initially seem like a promising direction for digital humanities development with Drupal; a project could work out the details of how to capture historical financial records, or build an art history catalog raisonné, then provide it as a distro for other scholars in the same field to use. However, the way distros work comes with some sustainability challenges that can make them highly problematic. The components of a distro -- Drupal core, as well as any modules required by the distro’s configuration -- are not intended to be updated individually by end-users. Distro creators are supposed to issue an update of the distro every time Drupal core or a constituent module releases an important update. For very complex distros, this makes sense; distros sometimes contain custom code that may break with the update, and distro creators need to test it and fix bugs before releasing it to the distro’s users. In practice, most digital humanities projects lack the staff and resources to support that kind of ongoing maintenance work for all the users of a distro. Sites that are built using an unmaintained distro get left in limbo, unable to make necessary security updates. Ripping out the underlying “plumbing” installed by a distro in order to return to a “vanilla” Drupal installation that can be updated is very time-consuming and challenging. Distros may also limit your ability to further customize your site. Unless a distro does precisely what you need, and you have confidence in the developer’s ability to provide updates in a reasonable timeframe, it is better to build a site using the normal version of Drupal available on drupal.org. Chapter 15 covers Features, an alternate way to share configuration work and move it between sites that doesn’t have the negative side-effects of distros.