Posted On: Sep 22, 2021

Starting today, you can use EC2 Fleet with targeted On-Demand Capacity Reservations. On-Demand Capacity Reservations enable you to reserve compute capacity for your Amazon EC2 instances in a specific Availability Zone for any duration. For targeted Capacity Reservations, instances must specifically target the Capacity Reservation to run in the reserved capacity. Until now, there was no option to use targeted Capacity Reservations when launching an EC2 Fleet.

You can use targeted Capacity Reservations with EC2 Fleet in the instant mode only. Before requesting an EC2 Fleet, you need to create a Capacity Reservations resource group, add your targeted Capacity Reservations to that group, and reference that group in your EC2 Fleet launch template. When launching, EC2 Fleet will first launch instances into Capacity Reservations in the referenced Capacity Reservations resource group if they match the instance type, platform, and Availability Zone combination. If the number of unused Capacity Reservations is less than the target capacity, EC2 Fleet will launch the remaining capacity based on your EC2 Fleet configuration. This feature is helpful when you run multiple EC2 Fleets and want to use your Capacity Reservations only in selected fleets.

The feature is available in all commercial AWS Regions except for Asia Pacific (Osaka), EU (Milano), Africa (Cape Town), and China (Beijing, Ningxia). Amazon EC2 Fleet simplifies the provisioning of EC2 capacity across different EC2 instance types, Availability Zones, and purchase models (On-Demand, Reserved Instances, Savings Plans, and Spot) to optimize your application’s scalability, performance, and cost. To learn more about using EC2 Fleet, please visit this page. To learn more about On-Demand Capacity Reservations, please visit this page. To learn more about using On-Demand Capacity Reservations with EC2 Fleet, please visit this page.