You can now update your existing Amazon Elastic Container Service (Amazon ECS) services that use a short Amazon Resource Name (ARN) to use a long ARN without needing to re-create the service. This enables you to tag your long-running Amazon ECS services, letting you better allocate cost, improve visibility, and define fine-grained resource-level permissions for these services.
Since 2018, customers have been able to tag Amazon ECS services that use the long ARN format (which includes the cluster name in the ARN) but if they wanted to tag services that were created with the old short ARN format, they had to delete and re-create the service. Now, ECS enables you to tag services that were created with the old short ARN format without needing to re-create the service. To enable this, you need to complete 2 steps: 1/opt-in your account to the long Amazon Resource Names (ARN) format for tasks and services and 2/tag the service you want to migrate to the long ARN format using the TagResource API action. Once you complete these steps, ECS updates the ARN of the service to the long ARN format and tags the service. Updating the service to use the long ARN format allows you to define resource-based access policies in IAM and granularly monitor the cost of your services in the Cost & Usage Report and Cost Explorer.
You can update your services with short ARNs to long ARNs in all AWS regions using the AWS Console, CLI, and API. To learn more, please read our documentation.
Source:: Amazon AWS