The origins of the term "blue-green deployment"
The blue-green story, as is so often the case, was about navigating a tricky client. The build team I was leading had figured out there were lots of differences between the test environments and production. (There were also differences between each of the test environments, but that’s another set of patterns!)
We figured the safest way to check a release was to deploy the app side-by-side onto the same physical boxes as the live system. We were running WebLogic which has the concept of a “domain”, which is just a directory full of application files. We would deploy the new version in an adjacent directory, which we called the “shadow domain” (which had a nice fantasy ring to it: “Prepare the shadow domain!” etc.), attach it to a local port, and smoke test it there by connecting directly to the port. Once we were happy with the deployment we could cut over th