Interruptible Capacity Reservations for capacity owners - Amazon Elastic Compute Cloud
Creating an interruptible Capacity ReservationView your interruptible Capacity ReservationModifying your interruptible Capacity ReservationReclamation process and tracking

Interruptible Capacity Reservations for capacity owners

The capacity owner is the account that owns the source Capacity Reservation and creates the interruptible Capacity Reservation to share unused capacity with other teams while retaining control to reclaim it when needed.

This section covers how you (the capacity owner) can create, modify, reclaim, and track an interruptible Capacity Reservation.

Creating an interruptible Capacity Reservation

Create an interruptible Capacity Reservation to make unused capacity from your source reservation available for other workloads while maintaining control to reclaim it when needed.

Prerequisites

Before creating an interruptible allocation, ensure your source On-Demand Capacity Reservation meets these requirements:

  • Your Capacity Reservation must be in active state with no end date set. You can't create allocations from reservations that are pending, expired, cancelled, or have scheduled end dates.

  • Your Capacity Reservation must have available capacity for allocation. You can only allocate available instances (also called unused capacity).

  • You can create only one interruptible allocation per source Capacity Reservation. If an allocation already exists, you must modify or cancel it before creating a new one.

  • You can allocate a maximum of 1000 instances at once to an interruptible Capacity Reservation.

Use can use the console or the AWS CLI to create an interruptible Capacity Reservation.

Console
To create an interruptible Capacity Reservation

  1. Open the Amazon EC2 console at https://console.aws.amazon.com/ec2/.

  2. Choose Capacity Reservations.

  3. Select your Capacity Reservation.

  4. Choose Actions, Create interruptible allocation.

  5. For Instances to allocate, enter the number of instances to allocate.

  6. (Optional) Add tags.

  7. Choose Create interruptible capacity allocation.

AWS CLI
To create an interruptible Capacity Reservation

Use the create-interruptible-capacity-reservation-allocation command:

aws ec2 create-interruptible-capacity-reservation-allocation \
    --capacity-reservation-id cr-1234567890abcdef0 \
    --instance-count 10

View your interruptible Capacity Reservation

After creating an interruptible Capacity Reservation, you can view the interruptible reservation in your account or from a specific resource.

View all interruptible Capacity Reservations in your account

Use the following procedure to view the interruptible Capacity Reservations in your account.

Console
To view the interruptible Capacity Reservations in your account

  1. Go to the Capacity Reservations page in the console.

  2. Look for reservations with Interruptible in the type column.

  3. Select the interruptible reservation to view details.

AWS CLI

To view the interruptible Capacity Reservations in your account

aws ec2 describe-capacity-reservations \
    --capacity-reservation-id cr-interruptible-id \
    --filters Name=interruptible,Values=true

View interruptible Capacity Reservation from a specific source

Use the following procedure to view the interruptible Capacity Reservation created from a specific source Capacity Reservation.

aws ec2 describe-capacity-reservations \
    --capacity-reservation-id cr-source-id

In the response, you'll find an interruptibleCapacityAllocations object that contains the interruptible Capacity Reservation ID and allocation details. For information about the response structure, see InterruptibleCapacityAllocation in the Amazon EC2 API Reference.

Modifying your interruptible Capacity Reservation

Use the following procedures to edit or cancel your interruptible Capacity Reservation.

Note

  • When you reduce the allocation, we first reclaim available instances, then running instances, until we meet the requested count. If we can meet the count entirely with available instances, no termination occurs. All modifications to allocated instance count are done through the source Capacity Reservation, not directly on the interruptible Capacity Reservation.

  • You can only modify an interruptible Capacity Reservation by a maximum of 1000 instances at once (increase or decrease).

Edit your interruptible Capacity Reservation

Use the following procedure to edit your interruptible Capacity Reservation.

Console

  1. From the source Capacity Reservation details page, choose Actions. Then, Edit interruptible Capacity Reservation.

  2. For Instances to allocate, enter the new number:

    • Add more capacity to share

    • Reclaim capacity to your source Capacity Reservation

  3. Choose Update.

AWS CLI
aws ec2 update-interruptible-capacity-reservation-allocation \
    --capacity-reservation-id cr-1234567890abcdef0 \
    --target-instance-count 80

Cancel your interruptible Capacity Reservation

Use the following procedure to permanently remove the allocation and return all capacity.

Console

  1. From the source Capacity Reservation details page, navigate to the interruptible capacity allocation details.

  2. Choose Edit interruptible allocation.

  3. For Instance count, enter 0.

  4. Choose Update.

AWS CLI
aws ec2 update-interruptible-capacity-reservation-allocation \
--capacity-reservation-id cr-1234567890abcdef0 \
--target-instance-count 0

Reclamation process and tracking

When you reclaim capacity:

  • Running instances receive a 2-minute interruption warning through EventBridge events.

  • After the notice period, running instances in the reclaimed capacity enter a shutting down state and get terminated.

  • When terminated, the reclaimed instances become available in your source Capacity Reservation for immediate use.

  • Your allocation status changes from updating to active when complete.

Complete reclamation can take a few minutes depending on instance type and shutdown time. For more information about the EventBridge notification you receive when the process is complete, see Reclamation completion.

Track reclamation status

Monitor reclamation progress by describing your source reservation:

aws ec2 describe-capacity-reservations \
--capacity-reservation-id cr-1234567890abcdef0

The response shows these fields within the interruptibleCapacityAllocation object:

  • instance-count: Current allocated instances

  • target-instance-count: Requested quantity after reclamation

  • status: updating during reclamation and active when complete

Sharing interruptible reservations

You can share interruptible reservations only within your AWS organization using AWS Resource Access Manager (RAM).

Considerations:

  • If a consumer account leaves your organization, the interruptible reservation is automatically unshared from that account.

  • Any instances running in the unshared reservation are eventually terminated.

  • All other sharing functionality works the same as standard Capacity Reservations.

For complete sharing procedures, see Sharing Capacity Reservations.