myApplications dashboard costs are incorrect f

Thank you for providing detailed information about your setup and the issue you're experiencing with the myApplications dashboard. Based on the information available, it appears that there might be some limitations or inconsistencies with how the myApplications dashboard handles cost allocation for ECS clusters running on EC2 instances.

The myApplications dashboard is designed to provide an overview of application metrics, including costs, across various AWS services. However, the behavior you're describing suggests that there might be a discrepancy in how costs are calculated or displayed for ECS on EC2 compared to Fargate.

It's important to note that the myApplications feature is relatively new, and while it supports a wide range of AWS services, there could be some edge cases or specific configurations that may not be fully accounted for in the cost calculations.

The fact that switching to Fargate results in correct cost reporting in the myApplications dashboard indicates that the feature does work correctly for containerized workloads in general. Fargate, being a serverless compute engine for containers, might have a more straightforward cost allocation mechanism that integrates more seamlessly with the myApplications dashboard.

For ECS on EC2, the cost allocation might be more complex due to the shared nature of EC2 instances in a cluster, especially when you have multiple tasks with different tags running on the same instances. The 'split cost allocation data' (SCAD) feature you enabled should theoretically help with this, but it seems it may not be fully integrated with the myApplications dashboard for this specific use case.

While I cannot definitively state whether this has been extensively tested for ECS/EKS on EC2, your experience suggests that there might be room for improvement in how the myApplications dashboard handles cost allocation for these scenarios.

Given this situation, you might want to:

1. Double-check that all resources (EC2 instances, ECS tasks, DynamoDB table, S3 bucket) are correctly tagged and associated with the right applications in AppRegistry.

2. Compare the costs shown in the myApplications dashboard with those in AWS Cost Explorer, using the same tags and time period, to see if there are any discrepancies.

3. Consider reaching out to AWS Support to report this behavior, as it could be a bug or limitation that needs to be addressed.

4. In the meantime, you might need to rely on other AWS cost management tools like AWS Cost Explorer or AWS Budgets for more accurate cost allocation for your ECS on EC2 workloads.

Remember that while the myApplications dashboard aims to provide a comprehensive view of your application metrics, it's still evolving, and there might be certain scenarios where it may not yet provide fully accurate information.
Sources
What is myApplications in AWS Console Home? - AWS Management Console
Govern Microsoft workloads using the myApplications dashboard on AWS | Microsoft Workloads on AWS
myApplications dashboard in AWS Console Home - AWS Management Console