How Blue-Green Deployments Work in Practice

Blue/green deployments offer a modern solution to minimize downtime and errors during application updates by utilizing two production environments, where one serves as a staging ground while the other remains live. This deployment strategy allows seamless transitions between application versions, facilitated by a load balancer that directs traffic to the active environment. The process involves duplicating production environments, managing data through versioned databases, and integrating with CI/CD pipelines to automate deployment and testing. Despite the complexity and costs associated with maintaining dual environments and advanced database handling, the approach effectively reduces service disruptions and allows for quick rollbacks if needed. Blue/green deployments are particularly beneficial for time-sensitive applications, enabling "test in production" scenarios and feature flagging. Tools like Earthly can aid in simplifying the build processes, making the transition more manageable.