You are configuring a blue/green deployment for an ECS application using AWS CodeDeploy and CloudFormation. During the deployment window the app must remain highly available and traffic should shift 10% to the new version every minute until fully shifted. What CloudFormation configuration accomplishes this?

The correct approach for blue/green deployments with ECS and CodeDeploy using CloudFormation is to leverage the AWS::CodeDeployBlueGreen transform. This transform orchestrates the blue/green deployment process within CloudFormation. The hook parameter within this transform allows you to specify a predefined CodeDeploy deployment configuration. CodeDeployDefault.ECSLinear10PercentEvery1Minutes is a built-in CodeDeploy configuration that shifts 10% of traffic every minute, matching the requirement. Including an AppSpec file is for defining deployment steps and hooks within CodeDeploy itself, not for configuring the CloudFormation blue/green transform. ECSCanary10Percent5Minutes is a different deployment strategy that shifts traffic over 5 minutes, not 1 minute, and is not the default linear option requested.