I have the following distributed JavaEE set up which I let run for exactly one day (24 hours) to check if I can reconstruct the costs manually. In order to generate some workload I used an Load Test Driver which runs on my local machine and emulates user requests to the system. I'm using the region EU (Frankfurt) and all my instances are in the same Availability Zone.
Now when I take a look at the Amazon Cost Reporter the following costs are reported. Here are the costs grouped by Instance Type:
And here are the costs grouped by API Operation:
The instance m4.xlarge costs $0.285 per Hour which means 3 x 24 x 0.285 = 20.52. That's exactly the same what the Amazon Cost Reporter says.
Now I have costs for RunInstances which is 22.80 and when I subtract the costs for the three instances I get 22.80 - 20.52 = 2.28.
The next thing I would to is to subtract the costs for the EBS Volumes which is $0.119 per GB-month of provisioned storage. So in my case I have 32GB * 0.119 = 3.808 per Month. In order to get the costs per day I divide it through 30.5 and get 3.808 / 30.5 = 0.125.
Now when I subtract the costs for the EBS Volumes from the remaining instance costs I get 2.28 - 0.125 = 2.155. But what now where do this remaining 2$ come from? Do I have some mistakes in my calculation or are there other costs I don't consider so far?
Any help or pointers would be appreciate.
