This is the story of how the Launchpad (https://launchpad.net) development team switched to a continuous integration system to increase several flows in their development process:

• flow of changes on trunk;
• flow of changes requiring database schema upgrade;
• flow of deployed changes to end users.

To switch to a buildbot (http://buildbot.net) based system meant violating a very old company taboo: risking a trunk that doesn’t pass its test suite. The risk of a broken trunk was offset by allowing each developer to run the full test suite in the Amazon EC2 cloud.