Launch instances into an existing Capacity Reservation - Amazon Elastic Compute Cloud

Launch instances into an existing Capacity Reservation

When you launch an instance, you can specify whether to launch the instance into any open Capacity Reservation, into a specific Capacity Reservation, or into a group of Capacity Reservations. You can only launch an instance into a Capacity Reservation that has matching attributes (instance type, platform, Availability Zone, and tenancy) and sufficient capacity. Alternatively, you can configure the instance to avoid running in a Capacity Reservation, even if you have an open Capacity Reservation that has matching attributes and available capacity.

Launching an instance into a Capacity Reservation reduces its available capacity by the number of instances launched. For example, if you launch three instances, the available capacity of the Capacity Reservation is reduced by three.

To launch instances into an existing Capacity Reservation using the console

  1. Follow the procedure to launch an instance, but don't launch the instance until you've completed the following steps to specify the settings for the placement group and Capacity Reservation.

  2. Expand Advanced details and do the following:

    1. For Placement group, select the cluster placement group in which to launch the instance.

    2. For Capacity Reservation, choose one of the following options depending on the configuration of the Capacity Reservation:

      • None – Prevents the instances from launching into a Capacity Reservation. The instances run in On-Demand capacity.

      • Open – Launches the instances into any Capacity Reservation that has matching attributes and sufficient capacity for the number of instances you selected. If there is no matching Capacity Reservation with sufficient capacity, the instance uses On-Demand capacity.

      • Specify Capacity Reservation – Launches the instances into the selected Capacity Reservation. If the selected Capacity Reservation does not have sufficient capacity for the number of instances you selected, the instance launch fails.

      • Specify Capacity Reservation resource group – Launches the instances into any Capacity Reservation with matching attributes and available capacity in the selected Capacity Reservation group. If the selected group does not have a Capacity Reservation with matching attributes and available capacity, the instances launch into On-Demand capacity.

      • Specify Capacity Reservation only – Launches the instances into a Capacity Reservation. If a Capacity Reservation ID isn't specified, the instances launch into an open Capacity Reservation. If capacity isn't available, the instances fail to launch.

      • Specify Capacity Reservation resource group only – Launches the instances into a Capacity Reservation in a Capacity Reservation resource group. If a Capacity Reservation resource group ARN isn't specified, the instances launch into an open Capacity Reservation. If capacity isn't available, the instances fail to launch.

  3. In the Summary panel, review your instance configuration, and then choose Launch instance. For more information, see Launch an EC2 instance using the launch instance wizard in the console.

To launch an instance into an existing Capacity Reservation using the AWS CLI

Use the run-instances command and specify the --capacity-reservation-specification parameter.

The following example launches a t2.micro instance into any open Capacity Reservation that has matching attributes and available capacity:

aws ec2 run-instances --image-id ami-abc12345 --count 1 --instance-type t2.micro --key-name MyKeyPair --subnet-id subnet-1234567890abcdef1 --capacity-reservation-specification CapacityReservationPreference=open

The following example launches a t2.micro instance into a targeted Capacity Reservation:

aws ec2 run-instances --image-id ami-abc12345 --count 1 --instance-type t2.micro --key-name MyKeyPair --subnet-id subnet-1234567890abcdef1 --capacity-reservation-specification CapacityReservationTarget={CapacityReservationId=cr-a1234567}

The following example launches a t2.micro instance into a Capacity Reservation group:

aws ec2 run-instances --image-id ami-abc12345 --count 1 --instance-type t2.micro --key-name MyKeyPair --subnet-id subnet-1234567890abcdef1 --capacity-reservation-specification CapacityReservationTarget={CapacityReservationResourceGroupArn=arn:aws:resource-groups:us-west-1:123456789012:group/my-cr-group}

The following example launches a t2.micro instance into a Capacity Reservation only. Because a Capacity Reservation ID isn't specified, the instance will launch in any open Capacity Reservation that has matching attributes and available capacity:

aws ec2 run-instances --image-id ami-abc12345 --count 1 --instance-type t2.micro --key-name MyKeyPair --subnet-id subnet-1234567890abcdef1 --capacity-reservation-specification CapacityReservationPreference=capacity-reservations-only

The following example launches a t2.micro instance into a specific Capacity Reservation only. If capacity isn't available in the specified Capacity Reservation, the instance will fail to launch.

aws ec2 run-instances --image-id ami-abc12345 --count 1 --instance-type t2.micro --key-name MyKeyPair --subnet-id subnet-1234567890abcdef1 --capacity-reservation-specification CapacityReservationPreference=capacity-reservations-only CapacityReservationTarget={CapacityReservationId=cr-a1234567}