Yesterday your boss asked you to demonstrate the great new features of your system to a customer, but you can’t show them anything. All your developers are halfway through developing new features and none of them can run the application right now. You have code, it compiles, and all the unit tests pass on your continuous integration server, but it takes a couple of days to release the new version into the publicly accessible UAT environment. Isn’t it unreasonable to expect the demo at such short notice?
Continuous Delivery. David Farley and Jez Humble