Agile 101: What is Continuous Integration?

What is Continuous Integration (CI)?

Continuous Integration (CI) is the practice of periodically executing Automated Build Scripts (ABS), preferably in short intervals. There are two flavors of this practice. The first flavor, mostly applied by early XP practitioners states that the system is built by one developer at any given time. The teams have adopted various physical tokens signifying the builders’ "right of build". In this flavor of CI Automated Build Scripts are still required, albeit the kicking off the build happens manually. Since this version relies heavily on the entire team to be colocated, it does not scale well in distributed Agile projects.

The second flavor of CI relies on a computer background process to poll the code repository in short intervals and automatically trigger the build process if it detects any changes since the last build. In this version of CI, the developer is only responsible to build locally and check-in the code. This model is better suited for highly scalable Agile teams because of its reliance on automated asynchronous processes to trigger the build. This gives distributed teams an early feedback on the status of the system and therefore it enables dislocated team members and managers to have the same quick feedback as the team itself.