With a blue/green deployment, you provision a new set of instances on which CodeDeploy installs the latest version of your application. CodeDeploy then reroutes load balancer traffic from an existing set of instances running the previous version of your application to the new set of instances running the latest version. After traffic is rerouted to the new instances, the existing instances can be terminated. Blue/green deployments allow you to test the new application version before sending production traffic to it. If there is an issue with the newly deployed application version, you can roll back to the previous version faster than with in-place deployments. Additionally, the instances provisioned for the blue/green deployment will reflect the most up-to-date server configurations since they are new.

With CodeDeploy, you can choose the specific settings for your blue/green deployments. For example, you can choose to manually provision the new instances or let CodeDeploy provision them for you by copying an existing Auto Scaling group. You can also choose when to reroute traffic to the new instances, the rate at which traffic is routed to them, and whether to terminate your old instances upon completion.

Learn more about this feature by visiting the documentation or by following the walkthrough.

For more information on AWS CodeDeploy: