Blue/Green Deployment | Glossary

Definition:

The blue/green is a strategy for change in management to releasing software code. Blue/green deployments, which may also be stated as A/B deployments require two identical hardware environments that are configured exactly the same way. While one environment is active and serving end users, the other environment remains idle.

Further Reading:

Book: The DevOps Handbook by Gene Kim, Jez Humble,Patrick Debois.