When Rossi is about to roll out an update, he initiates a checkin procedure on IRC. All of the developers who have submitted code for inclusion in the pending update are notified in the channel and have to respond to verify that they are present and ready for the update to go out.
When a developer doesn’t respond within a few minutes, Rossi can send a command to a bot that will attempt to get the developer’s attention through several different communication channels, including e-mail and text messages. As Rossi explained to me, he typically prefers to have all of the contributing developers on hand when deploying an update.
An important aspect of Facebook’s development culture is the idea that developers are fully responsible for how their code behaves in production. This philosophy mirrors the “DevOps” movement, which encourages lowering the wall between software development and IT operations.
(Full Story: Behind-the-scenes look at Facebook release engineering)