# Migrating from a CodeDeploy blue/green to an Amazon ECS blue/green service deployment
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 By using Amazon ECS blue/green deployments, you can make and test service changes before implementing them in a production environment. 

You must create new lifecycle hooks for your Amazon ECS blue/green deployment.

## Prerequisites
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Perform the following operations before you start a blue/green deployment.

1. Replace the Amazon ECS CodeDeploy IAM role with the following permissions.
   + For information about Elastic Load Balancing permissions, see [Amazon ECS infrastructure IAM role for load balancers](AmazonECSInfrastructureRolePolicyForLoadBalancers.md).
   + For information about Lambda permissions, see [Permissions required for Lambda functions in Amazon ECS blue/green deployments](blue-green-permissions.md).

1. Turn off CodeDeploy automation. For more information, see [Working with deployment groups in CodeDeploy](https://docs.amazonaws.cn/codedeploy/latest/userguide/deployment-groups.html) in the *CodeDeploy User Guide*. 

1. Make sure that you have the following information from your CodeDeploy blue/green deployment. You can reuse this information for the Amazon ECS blue/green deployment:
   + The production target group
   + The production listener
   + The production rule
   + The test target group

     This is the target group for the green service revision,

1. Ensure that your Application Load Balancer target groups are properly associated with listener rules:
   + If you are not using test listeners, both target groups (production and test) must be associated with production listener rules.
   + If you are using test listeners, one target group must be linked to production listener rules and the other target group must be linked to test listener rules.

   If this requirement is not met, the service deployment will fail with the following error: `Service deployment rolled back because of invalid networking configuration. Both targetGroup and alternateTargetGroup must be associated with the productionListenerRule or testListenerRule.`

1. Verify that there are no ongoing service deployments for the service. For more information, see [View service history using Amazon ECS service deployments](service-deployment.md).

1. Amazon ECS blue/green deployments require your service to use one of the following features: 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).

1. Decide if you want to run Lambda functions for the lifecycle stages for the stages in the Amazon ECS blue/green deployment.
   + Pre scale up
   + After scale up
   + Test traffic shift
   + After test traffic shift
   + Production traffic shift
   + After production traffic shift

   Create Lambda functions for each lifecycle stage. For more information, see [Create a Lambda function with the console](https://docs.amazonaws.cn/lambda/latest/dg/getting-started.html#getting-started-create-function) in the *Amazon Lambda Developer Guide*.

For more information about updating a service's deployment controller, see [Update Amazon ECS service parameters](update-service-parameters.md).

## Procedure
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1. Open the console at [https://console.amazonaws.cn/ecs/v2](https://console.amazonaws.cn/ecs/v2).

1. On the **Clusters** page, choose the cluster.

   The cluster details page displays.

1. From the **Services** tab, choose the service.

   The service details page displays.

1. In the banner, choose **Update deployment controller type**.

   The **Migrate deployment controller type** page displays.

1. Expand **New**, and then specify the following parameters.

   1. For **Deployment controller type**, choose **ECS**.

   1. For **Deployment strategy**, choose **Blue/green**.

   1. For **Bake time**, enter the time that both the blue and green service revisions run.

   1. To run Lambda functions for a lifecycle stage, under **Deployment lifecycle hooks** do the following for each unique Lambda function:

      1. Choose **Add**.

         Repeat for every unique function you want to run.

      1. For **Lambda function**, enter the function name.

      1. For **Role**, choose the role that you created in the prerequisites with the blue/green permissions.

         For more information, see [Permissions required for Lambda functions in Amazon ECS blue/green deployments](blue-green-permissions.md).

      1. For **Lifecycle stages**, select the stages the Lambda function runs.

      1.  (Optional) For **Hook details**, enter a key-value pair that provides information about the hook.

1. Expand **Load Balancing**, and the configure the following:

   1. For **Role**, choose the role that you created in the prerequisites with the blue/green permissions.

      For more information, see [Permissions required for Lambda functions in Amazon ECS blue/green deployments](blue-green-permissions.md).

   1. For **Listener**, choose the production listener from your CodeDeploy blue/green deployment.

   1. For **Production rule**, choose the production rule from your CodeDeploy blue/green deployment.

   1. For **Test rule**, choose the test rule from your CodeDeploy blue/green deployment.

   1. For **Target group**, choose the production target group from your CodeDeploy blue/green deployment.

   1. For **Alternate target group**, choose the test target group from your CodeDeploy blue/green deployment.

1. Choose **Update**.

## Next steps
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+ Update the service to start the deployment. For more information, see [Updating an Amazon ECS service](update-service-console-v2.md).
+ Monitor the deployment process to ensure it follows the blue/green pattern:
  + The green service revision is created and scaled up
  + Test traffic is routed to the green revision (if configured)
  + Production traffic is shifted to the green revision
  + After the bake time, the blue revision is terminated