# DeploymentController
<a name="API_DeploymentController"></a>

The deployment controller to use for the service. 

## Contents
<a name="API_DeploymentController_Contents"></a>

 ** type **   <a name="ECS-Type-DeploymentController-type"></a>
The deployment controller type to use.  
The deployment controller is the mechanism that determines how tasks are deployed for your service. The valid options are:  
+ ECS

  When you create a service which uses the `ECS` deployment controller, you can choose between the following deployment strategies:
  +  `ROLLING`: When you create a service which uses the *rolling update* (`ROLLING`) deployment strategy, the Amazon ECS service scheduler replaces the currently running tasks with new tasks. The number of tasks that Amazon ECS adds or removes from the service during a rolling update is controlled by the service deployment configuration. 

    Rolling update deployments are best suited for the following scenarios:
    + Gradual service updates: You need to update your service incrementally without taking the entire service offline at once.
    + Limited resource requirements: You want to avoid the additional resource costs of running two complete environments simultaneously (as required by blue/green deployments).
    + Acceptable deployment time: Your application can tolerate a longer deployment process, as rolling updates replace tasks one by one.
    + No need for instant roll back: Your service can tolerate a rollback process that takes minutes rather than seconds.
    + Simple deployment process: You prefer a straightforward deployment approach without the complexity of managing multiple environments, target groups, and listeners.
    + No load balancer requirement: Your service doesn't use or require a load balancer, Application Load Balancer, Network Load Balancer, or Service Connect (which are required for blue/green deployments).
    + Stateful applications: Your application maintains state that makes it difficult to run two parallel environments.
    + Cost sensitivity: You want to minimize deployment costs by not running duplicate environments during deployment.

    Rolling updates are the default deployment strategy for services and provide a balance between deployment safety and resource efficiency for many common application scenarios.
  +  `BLUE_GREEN`: A *blue/green* deployment strategy (`BLUE_GREEN`) is a release methodology that reduces downtime and risk by running two identical production environments called blue and green. With Amazon ECS blue/green deployments, you can validate new service revisions before directing production traffic to them. This approach provides a safer way to deploy changes with the ability to quickly roll back if needed.

    Amazon ECS blue/green deployments are best suited for the following scenarios:
    + Service validation: When you need to validate new service revisions before directing production traffic to them
    + Zero downtime: When your service requires zero-downtime deployments
    + Instant roll back: When you need the ability to quickly roll back if issues are detected
    + Load balancer requirement: When your service uses Application Load Balancer, Network Load Balancer, or Service Connect
+ External

  Use a third-party deployment controller.
+ Blue/green deployment (powered by AWS CodeDeploy)

   AWS CodeDeploy installs an updated version of the application as a new replacement task set and reroutes production traffic from the original application task set to the replacement task set. The original task set is terminated after a successful deployment. Use this deployment controller to verify a new deployment of a service before sending production traffic to it.
Type: String  
Valid Values: `ECS | CODE_DEPLOY | EXTERNAL`   
Required: Yes

## See Also
<a name="API_DeploymentController_SeeAlso"></a>

For more information about using this API in one of the language-specific AWS SDKs, see the following:
+  [AWS SDK for C\$1\$1](https://docs.aws.amazon.com/goto/SdkForCpp/ecs-2014-11-13/DeploymentController) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/ecs-2014-11-13/DeploymentController) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/ecs-2014-11-13/DeploymentController)