An e-commerce company wants to release a major update to its checkout system. Since downtime directly affects sales and customer experience, they need a deployment strategy that allows a smooth transition without downtime.
- The company has a live checkout system running on the Blue environment (production).
- They want to deploy version 2.0 of the checkout system, which includes significant improvements and new features.
- Preparation: The current production environment is referred to as Blue. A new environment (let's call it Green) is provisioned. This environment is a replica of the Blue environment but runs the new version 2.0 of the checkout system.
- Deployment: Version 2.0 of the checkout system is deployed to the Green environment. The team runs tests on the Green environment, ensuring that all critical functions (like payments and order confirmations) are working as expected.
- Switching Traffic: After testing and validation, the load balancer is reconfigured to direct all traffic from Blue to Green. All users are now interacting with version 2.0.
- Monitoring: Post-deployment monitoring begins. If any major issues are detected, the traffic can be switched back to the Blue environment almost immediately.
- Rollback (if necessary): If a serious issue arises after the switch, the company can instantly revert back to the Blue environment by updating the load balancer settings, ensuring minimal disruption to customers.
An online retailer like Amazon might use Blue-Green deployment to release a new feature like "one-click checkout." They cannot afford downtime, so they create a Green environment to test the feature in production-like conditions. Once tested, all user traffic is routed to Green without any noticeable downtime, and if there’s an issue, they can quickly revert to the old Blue environment.
- Blue-Green Deployment is ideal when you need a quick, clean switch between two environments and are confident in your ability to fully validate the new version before exposing all users to it.
