Rightsizing Report shows $0 in Savings despite having a rightsizing recommendation

Products

• CloudHealth

Issue/Introduction

This normally has to do with the EC2 instances being covered by Savings Plans in some way.  Here is how the “Savings” column is calculated:

Recommendation Savings = (Actual Compute Cost of EC2 Instance) – (On-demand Price of Recommended EC2 Instance)

Querying a few instances in the EC2 Instance Hours Report, you can add a column called “% Savings Plan Covered” (via "Edit Columns").  You may see that the instances showing $0 savings are covered via Savings Plans:

Rightsizing Report

 

EC2 Instance Hours Report

Resolution

For the instances that are currently being covered by Savings Plans, their Actual Compute Cost may be less than List Price.  The Rightsizing report is therefore unable to report on estimated monthly savings for EC2 instances that have an Actual Compute Cost (charges in the AWS bill) lower than the List Price.  Therefore, the Savings column shows savings for these instances as $0.00.

For instances already covered by reservations or other discounts (such as Savings Plans), CloudHealth recommends comparing the Current Price column ($63.62, in the screenshot example), which shows the list price of the source instance, with the Recommended Price column ($30.35, in the screenshot example), which shows the list price of the least expensive instance that can manage the workload of the source instance.  By comparing these two amounts, you can better understand potential benefits of using the recommended instance.