Monitoring your size flexible reservations for Amazon EC2
Amazon EC2 Reserved Instances that apply to a Region provide Availability Zone flexibility and instance size flexibility. Reserved Instances that provide Availability Zone flexibility provide a discount on usage in any Availability Zone in the Region. Reserved Instances that provide instance size flexibility provide a discount on usage, regardless of instance size in that family. Size flexible Reserved Instances apply to the smallest instance sizes first. For more information, see How Reserved Instances are applied in the Amazon EC2 User Guide for Linux Instances.
To understand how instance size flexibility provided by your Reserved Instance is applied to your usage, refer to the lineItem/NormalizationFactor and lineItem/NormalizedUsageAmount columns.
Note
Instance size flexibility is supported only by Linux or Unix Reserved Instances with default tenancy that are assigned to a Region. For more information on the limitations of instance size flexibility for Regional Reserved Instances, see How regional Reserved Instances are applied in the Amazon EC2 User Guide for Linux Instances.
In a Cost and Usage Report, the Reserved Instance usage is applied by default to the account that purchased the Reserved Instance. Any available Reserved Instance benefit that the purchasing account can’t use within the hour is then applied to other linked accounts based on the available matching On-Demand Instance usage.
Example
You purchase one m4.xlarge RI in a given Region. This
m4.xlarge RI can be applied automatically to all
m4 instance usage in the same Region. In the following table,
AWS applied the m4.xlarge to two separate m4.large
instances.
| lineItem/LineItemType | RIFee | Discounted Usage | Discounted Usage |
| lineItem/ProductCode | AmazonEC2 | AmazonEC2 | AmazonEC2 |
| lineItem/UsageStartDate | 2016-01-01T00:00:00Z | 2016-01-01T00:00:00Z | 2016-01-01T00:00:00Z |
| lineItem/UsageType | HeavyUsage:m4.xlarge | BoxUsage:m4.large | BoxUsage:m4.large |
| lineItem/LineItemDescription | USD 0.0618 hourly fee per Linux/UNIX (Amazon VPC), m4.xlarge instance | Linux/UNIX (Amazon VPC), m4.large Reserved Instance applied | Linux/UNIX (Amazon VPC), m4.large Reserved Instance applied |
| lineItem/ResourceId | i-1bd250bc | i-1df340ed | |
| lineItem/UsageAmount | 1 | 1 | |
| lineItem/NormalizationFactor | 4 | 4 | 4 |
| lineItem/NormalizedUsageAmount | 4 | 4 | |
| lineItem/UnblendedRate | 0 | 0 | |
| lineItem/UnblendedCost | 46 | 0 | 0 |
| Reservation/ ReservationARN | arn:aws:ec2:us-east-1: 123456789012:reserved-instances /f8c204c1 | arn:aws:ec2:us-east-1: 123456789012:reserved-instances /f8c204c1 | arn:aws:ec2:us-east-1: 123456789012:reserved-instances /f8c204c1 |
| Reservation/TotalReservedUnits | 744 | ||
| Reservation/TotalReserved NormalizedUnits | 5952 |
The two m4.large usage line items have different
ResourceIds, and both received a discount benefit from
the single m4.xlarge RI. This is shown by matching the
reservationARN value across the usage and recurring
monthly charge line items.
For more information about RI purchase options, see How you are billed in the Amazon EC2 User Guide for Linux Instances.
