# Required resources for Amazon ECS linear deployments
<a name="linear-deployment-implementation"></a>

To use a linear deployment with managed traffic shifting, your service must use one of the following features:
+ Elastic Load Balancing
+ Service Connect

The following list provides a high-level overview of what you need to configure for Amazon ECS linear 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 `linear` in your service definition.
+ Optionally, configure additional parameters such as:
  + Bake time for the new deployment
  + The percentage of traffic to shift in each increment.
  + The duration in minutes to wait between each traffic shift increment. 
  + CloudWatch alarms for automatic rollback
  + Deployment lifecycle hooks (Lambda functions or pause hooks that run at specified deployment stages)

## Best practices
<a name="linear-deployment-best-practices"></a>

Follow these best practices for successful Amazon ECS linear deployments:
+ **Ensure your application can handle both 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.**
+ Configure appropriate health checks that accurately reflect your application's health.
+ Set a bake time that allows sufficient testing of the new service revision.
+ Implement CloudWatch alarms to automatically detect issues and trigger rollbacks.
+ Choose step percentages and bake times that balance deployment speed with validation needs.
+ Use smaller step percentages (5-10%) for critical applications to minimize risk exposure.
+ Set longer step bake times for applications that need time to warm up or stabilize.
+ Implement CloudWatch alarms to automatically detect issues and trigger rollbacks at any traffic increment.
+ Monitor application metrics closely during each traffic shift to detect performance degradation early.
+ Ensure your application can handle both service revisions running simultaneously.
+ Test your rollback procedures at different traffic percentages before implementing them in production.