Do i get charged for Reserved Capacity if the machine is off?


I understand that an EC2 instance is only charged if it is on. But does it change if I use "Reserved Capacity"? If I run an EC2 On Demand instance with Reserved Capacity for a few hours a day only, do I get charged any more than the actual instance cost for those hours the machine is on?

已提問 2 年前檢視次數 740 次
2 個答案

Hi, @rberga.

Yes. Capacity Reservation is charged on-demand while provisioning is active.

Capacity Reservation pricing and billing - Amazon Elastic Compute Cloud

Billing starts as soon as the Capacity Reservation is provisioned in your account, and it continues while the Capacity Reservation remains provisioned in your account.

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已回答 2 年前
  • Even if the machine is off?

  • Yes. You will also be charged if the machine is down.
    However, you will still enjoy the benefits of making sure it launches the next time you launch it.
    Ideal for use cases where you cannot avoid the outage but want to start it reliably.

  • If you're choosing Reserved Capacity only for the savings you might consider Savings Plans instead.


Just to clarify (to make sure there are no confusions between Reserved Instances and Reserved Capacity):

  • If you talk about On-Demand Capacity Reservation (ODCR) - this is a feature normally used if you run critical workload and need to have the capacity you require when you start/launch your instance. In this case, you pay either for the instance that's running inside that capacity reservation, OR you still pay for the idle capacity reservation while the instance is not running.
  • If you mean Reserved Instances - these are mostly used to benefit from the long-term savings for workloads running 24/7 or close to 24/7. You pay for the RI for the full term, regardless if you actually run any matching EC2 instances or not during certain hours of the day.

Depends on the use case. If you are seeking to reserve capacity - ODCR is the right feature. If you are looking for BOTH reserving capacity AND getting billing discount - you can couple ODCR with Savings Plans or Regional Reserved Instances. If you only care about the discount, you should evaluate if your instance will run close to 24/7. Because if not, buying Savings Plan or Reserved Instance may not work for you, as it may end up being more expensive than simply running your instance on-demand for a couple of hours during the day (to make it cheaper, consider Spot pricing; it may be not for all workloads, but if you only run your instance for short periods of time and can handle interuptions - Spot will be the cheapest instance purchasing option).

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已回答 2 年前

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