You can now reserve Amazon EC2 capacity for any duration with On-Demand Capacity Reservations. Amazon EC2 provides a wide selection of instance types as well as over 50 global Availability Zones where you can run your applications. Some customers however have very specific requirements for portions of their applications around instance type, size, and capability, as well as the Availability Zone the instance needs to run in, and need very high levels of assurance that they will always be able to launch that specific capacity. Previously in order to achieve a capacity reservation, customers had to leverage Zonal Reserved Instances and commit to that capacity for a minimum of one year. Now with On-Demand Capacity Reservations, customers can reserve the exact capacity they need, in the location they need, and can keep it only for as long as they need it.

On-Demand Capacity Reservations are activated as soon as they are requested, and they stay active until cancelled. A Capacity Reservation is tied to a specific Availability Zone and, by default automatically utilized by running instances in that Availability Zone. Instances you have placed Capacity Reservations for are charged at the normal instance rate for as long as you maintain the reservation. Should you no longer need them, you can cancel your Capacity Reservation at any time to stop paying.

If you have Regional RI discounts, they will automatically apply to any matching Capacity Reservation. This gives you the flexibility to selectively add capacity reservations and still get the Regional RI discounts for that usage.

To get started, you can create an On-Demand Capacity Reservation by simply choosing an Availability Zone and quantity (number of instances) along with other instance specifications such as instance type and tenancy. Once created, the Capacity Reservation will ensure that you will always be able to launch that specific EC2 configuration.

On-Demand Capacity Reservations are now available in all public Regions. You can create and manage Capacity Reservations through the AWS Management Console, AWS SDK and CLI. To learn more about Capacity Reservations and how to use them, visit FAQs, Linux or Windows technical documentations.