# Required resources for Amazon ECS blue/green deployments
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To use a blue/green deployment with managed traffic shifting, your service must use one of the following features:
+ Elastic Load Balancing
+ Service Connect

Services that don't use Service Discovery, Service Connect, VPC Lattice or Elastic Load Balancing can also use blue/green deployments, but don't get any of the managed traffic shifting benefits.

The following list provides a high-level overview of what you need to configure for Amazon ECS blue/green deployments:
+ Your service uses an Application Load Balancer, Network Load Balancer, or Service Connect. Configure the appropriate resources.
  + Application Load Balancer - For more information, see [Application Load Balancer resources for blue/green, linear, and canary deployments](alb-resources-for-blue-green.md).
  + Network Load Balancer - For more information, see [Network Load Balancer resources for Amazon ECS blue/green, linear and canary deployments](nlb-resources-for-blue-green.md).
  + Service Connect - For more information, see [Service Connect resources for Amazon ECS blue/green, linear, and canary deployments](service-connect-blue-green.md).
+ Set the service deployment controller to `ECS`.
+ Configure the deployment strategy as `blue/green` in your service definition.
+ Optionally, configure additional parameters such as:
  + Bake time for the new deployment
  + CloudWatch alarms for automatic rollback
  + Deployment lifecycle hooks for testing (these are Lambda functions that run at specified deployment stages)

## Best practices
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Follow these best practices for successful Amazon ECS blue/green deployments:
+ Configure appropriate health checks that accurately reflect your application's health.
+ Set a bake time that allows sufficient testing of the green deployment.
+ Implement CloudWatch alarms to automatically detect issues and trigger rollbacks.
+ Use lifecycle hooks to perform automated testing at each deployment stage.
+ Ensure your application can handle both blue and green service revisions running simultaneously.
+ Plan for sufficient cluster capacity to handle both service revisions during deployment.
+ Test your rollback procedures before implementing them in production.