Clarification on Split Cost Calculation

[iMilad]

Quick question about how the Batch costs are calculated in the dashboards. I noticed a bit of a mismatch and wanted to check if I'm missing something obvious.

So from what I understand, the split cost for Batch is calculated based on the Compute and memory (used + unused) of the EC2 instances. But when I compare the numbers across tools, they don’t quite line up. (AWS Blog Source)

For example, when I check Cost Explorer for EC2-Instance usage in February, I see:

• Cost Explorer EC2-Instance total: $1,580.66

But in Grafana, the sum of team costs for the same period comes out to:

• Grafana total: ~$4,627

I also queried Athena directly to double-check, and it aligns more with what Grafana is showing — so not sure what Cost Explorer is excluding (or what we're maybe double-counting?).

Just wanted to clarify:

• What services are included under Batch in the split cost allocation?
• If it’s really just CPU and memory (used + unused) from EC2, do you have any idea why this difference might show up?

Appreciate any insight — thanks!

[mhuguesaws]

Thank you for reporting. We'll take a look.

[mhuguesaws]

Still looking at this issue. We should have billing data tomorrow. The new tag was not enabled in cost allocation tags.

[mhuguesaws]

I run a test on April 17th for 3 minutes of runtime using AWS Batch with ECS on a c5.large instance. The job was requesting 2 vCPUs + 500MB of memory.
The EC2 instance cost for that test was $0.00576113 in cost explorer. It is reflected in the AWS Batch cost dashboard solution through Cost and Usage Report split Cost allocation as $0.00576. Grafana is set with auto demical and if one added 10 decimal one will see the exact same cost as cost explorer ($0.00576113)

Dashboard solution

CSV from Cost Explorer

[iMilad]

Did you also test with the teams? because the numbers don't match when we sum of the cost for teams and then compare it in Cost Explorer.
We did not apply any changes in this deployment, but what we see in Grafana does not add up with Cost Explorer.

[mhuguesaws]

What does teams mean here? There is only notion of project in the dashboard.

[iMilad]

yes, I meant the project. so you ran multiple jobs from different projects on one EC2 (Batch Compute Env) and the result of the cost was identical to EC2 Compute cost in Cost Explorer, right?
please correct us if we are wrong, EC2 Compute Cost in Cost Explorer must be equal to ex. Projects Used and Unused EC2 compute cost.

[mhuguesaws]

I run one job to check that the job cost is equal to the EC2 instance cost. I'll run multiple projects jobs and come back.

[mhuguesaws]

Still waiting on the cost data to show in my console.

[mhuguesaws]

Cost explorer is populated. Not the cost usage and report yet.

[mhuguesaws]

Got the data and I am able to reproduce what you see. Let me dig further.

[cyberchip-wang]

Once I used the AWSBatchServiceTag=batch (need to enable) as a filter, my Cost Explorer bill from EC2-Instances resource was reduced significantly. As the split cost is not applicable to the standalone EC2 instances. There might be more to be found out.

[mhuguesaws]

@iMilad can you open a support case?

[iMilad]

@mhuguesaws on AWS you mean? if yes, why?