How do AWS credits apply to SP-covered and RI-covered usage when credit sharing is turned off?

Question

Hi,

Assuming we have two accounts, A and B, with Reserved Instance (RI) sharing turned ON and credit sharing turned OFF, let's review the scenario:

- Account A utilizes 720 hours each of m5.large, r5.large, and c5.large instances in a given month.
- Account B holds an m5.large No-Upfront RI, an r5.large All-Upfront RI, and a No-Upfront Compute Savings Plan, all of which are applied to Account A's usage.
- Account A receives EC2 credits, which it wishes to apply to its usage. Credits cannot be applied to Account B's usage due to the credit sharing being turned off.

Here are the questions:
1. Would credits apply to m5.large usage covered by No-Upfront RI from Account B? If yes, what would be the dollar amount of the credit - the full cost or discounted?

2. Would credits apply to r5.large usage covered by All-Upfront RI from Account B? If yes, what would be the dollar amount of the credit - the full cost or discounted?

3. Would credits apply to c5.large usage covered by No-Upfront Savings Plan from Account B? If yes, what would be the dollar amount of the credit - the full cost or discounted?

Dmitry · Accepted Answer

I received the following answer from AWS support, which I interpret as "usage covered by SPs/RIs doesn't receive credits":

*In general, promotional credits are applied after the Savings Plans discounts. The order of application for this scenario is as follows:*

- *If available, AWS Free Tier benefits are applied first.*
- *Savings Plans discounts are then applied to the remaining eligible usage, providing discounts on the On-Demand rates.*
- *After Savings Plans discounts, any remaining usage charges can be covered by promotional credits if the credits are applicable to that service.*

*Usually, the hourly rates that you pay for running instances can be covered by your promotional credits when you have Partial Upfront, or No Upfront Savings Plans. However, since Account A has credits sharing off, this won't be the case for the hourly rate for the Savings Plans on Account B.*

*In short, the Account A will get the discounted rate from the shared Savings Plans from account B applied first. Then if there's any remaining usage, the promotional credits will be applied. Account B won't get any benefit from the promotional credits on Account A.*

I then followed up for clarifications:
 Could you please clarify the term "remaining usage"?

E.g. I have $10,000 in EC2 credits in Account A

My usage for the month in Account A was $10,000 before discounts, but a Savings Plan from another account covered half of that with a 50% discount.

So my unblended costs are $5,000, and my amortized costs are $7,500.

What would be my "remaining usage" eligible for EC2 credits? $5,000 or $7,500?

The reply was:

*The discounted rate of the Savings Plan shared will cover any eligible EC2 on-demand usage. In case that there was still EC2 on-demand usage, then the promotional credits will be applied.*

*So, if the total EC2 on-demand usage was 10k, and the Savings Plan covered 50% of it, then the credits will be applied to the remaining 50% of the total on-demand usage. In other words, up to $5.000 of credits will be applied.*

Riku_Kobayashi · Answer

Hello.

"All-Upfront RI" should have paid all fees in advance, so I don't think the credit will be applied.  
With No-Upfront, I think you can cover your hourly or monthly fees with credits.  
https://repost.aws/knowledge-center/credits-ri  
> Check the "See complete list of services" list of eligible services that come under "Applicable products" for the credits redemption. If you purchase a Compute Savings plan at "NO upfront", your AWS credits can be used to cover the recurring hourly or monthly charges for the commitment. The credits will be applied to the discounted hourly rates for the usage covered by the covered by the Savings Plan. However, the credits cannot be used for any "upfront" costs associated with Partial Upfront or All Upfront Savings Plans Purchased. The credits can only offset the recurring usage charges when using No Upfront or Partial Upfront Savings Plans.

How do AWS credits apply to SP-covered and RI-covered usage when credit sharing is turned off?

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