Blue-Green Deployments for Safer Zero-Downtime Releases
A blue-green deployment keeps two production-capable application environments. One serves live traffic while the other receives the new release. After validation, traffic is switched to the candidate environment.
The pattern can make rollback fast, but it does not automatically make a release safe. Database changes, background jobs, caches, and external side effects can still make an old version incompatible with the new state.
The basic release sequence Assume blue is currently live and green will run the new version.
