Blue-Green Deployment

Blue-green deployment is a method of releasing new software versions with minimal downtime and risk. It involves running two production environments, blue and green. The live application runs on one environment, say blue, while the new release is deployed on the other, green. Once the new version is verified on green, traffic is routed from blue to green with a load balancer.

This technique allows quick rollback if issues emerge with the new release. You simply switch traffic back to the blue environment running the previous stable version. Blue-green deployment facilitates continuous delivery by reducing downtime and risk. For example, a SaaS company could use it to frequently update their cloud-hosted application. They would alternate between two identical cloud environments, deploying new releases to the inactive one. This would allow fast, low-risk upgrades for customers.