The Blue-Green Deployment in an environment based release pattern, in which two (as far as possible) identical environments - Blue and Green - exist, which each hold a different version of the software. The pattern goes as follows: Blue holds the current (old) version of software and receives all traffic. The deployment first installs the new version in Green, then switches over the traffic.
A rollback to the previous version is equally easy as a deployment of a new version, minus the installation of the version itself.
A Blue-Green Deployment requires an application architecture that has a centralized routing component, from which the Blue or the Green environment can be targeted.
- Does not address failing services (see Canary Deployment)