Validating Projected Cost field in AWS EC2 Rightsizing

Products

• CloudHealth

Issue/Introduction

Under AWS EC2 Rightsizing when using the "Actual Price" cost type, the current cost for an Instance may look like returned from the tool as if it had run for the entire month. 

Resolution

To validate the figure you can utilize the following formula:

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Estimated Usage Hours -

Total Hours = pull from the EC2 Instance Hours Report 
Days passed in current month = Check current UTC date
Days passed in current month in hours = 24* Days passed in current month
Number of days in the current month in hours = This ones on you heroes. 

estimatedHoursCalculation = (totalHours/daysPassedInCurrentMonthInHours) * numberOFDaysInCurrentMonthInHours

ESR -

Pull at the Instance level via a FlexReport, and compare Public On Demand Cost to SPEffective (RI)EffectiveCost, or associated NetFields as the tool does take into account EDP discounts.

Difference = Public OnDemand Cost - (NetSPEffective Cost || NetEffective Cost || SP Effective Cost || Effective Cost)

ESR = Difference/Public On Demand Cost * 100


Projected Cost = price * esr * estimatedUsageHours

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The figure should be close to that reported by the tool currently, but maybe off slightly as the dataset used by the tool is generated utilizing older datasets.