introduction to scheduled capacity reservations - Elastic Compute Service

A scheduled capacity reservation reserves resources in a private pool from a specified time, guaranteeing instance creation for your workloads.

How it works

Scheduled capacity reservations include two types: capacity reservations with Savings Plan and capacity reservations for subscription resources.

Capacity reservation with Savings Plan

A capacity reservation with Savings Plan ensures that pay-as-you-go instances can be created.

Purchase a capacity reservation with Savings Plan. Specify the zone, instance type, effective time, and other attributes.
The capacity reservation takes effect at the specified time. Use the private pool capacity to create pay-as-you-go instances during the validity period. The associated savings plan offsets the hourly fees of these instances.

Note

Savings plans offset the costs of compute resources (vCPUs and memory), images, system disks, data disks (including disk capacity, performance provision, and performance burst), and public bandwidths. Other instance resources are billed on actual usage. See Overview.

When a capacity reservation with Savings Plan is released manually or expires, the system stops reserving resources.

Note

After the capacity reservation is released, existing pay-as-you-go instances continue to run. The savings plan stops offsetting their fees, and the instances are billed on the pay-as-you-go billing method.

The following figure shows the process of reserving resources for two instances with a capacity reservation with Savings Plan.

Capacity reservation for subscription resources

A capacity reservation for subscription resources ensures that subscription instances can be created.

Purchase a capacity reservation for subscription resources. Specify the zone, instance type, effective time, and other attributes.
Alibaba Cloud receives the order, starts stocking, and sends an effective notification after stocking is complete.
After you receive the effective notification, use the private pool capacity to create subscription instances during the validity period. You must pay upfront for the instances.

Note

The capacity reservation ensures that subscription instances can be created, but does not guarantee operations such as configuration changes and renewals of existing instances. The minimum subscription duration is one month.

When the private pool capacity is exhausted or the validity period expires, the system stops reserving resources.

The following figure shows the process of reserving resources for two subscription instances.

Billing method

Time period	Capacity reservation with Savings Plan	Capacity reservations for subscription resources
When purchasing	Only No Upfront savings plans are supported. You do not need to pay upfront when you purchase a capacity reservation.	You do not need to pay upfront when you purchase a capacity reservation.
When using	You are charged for the No Upfront savings plan. The savings plan offsets the fees of idle capacity and pay-as-you-go instances. The savings plan offsets fees only for compute resources (vCPUs and memory), system disks, and public bandwidths of pay-as-you-go instances. Other resources are billed on actual usage.	Idle capacity is billed on the pay-as-you-go billing method. To create subscription instances, you must pay upfront.

Limitations

Only specific regions and instance types support scheduled capacity reservations. See the Create Resource Reservation page.
You cannot release capacity reservations for subscription resources or inactive capacity reservations with Savings Plan.

Use cases

A company plans to migrate its internal service platform to the cloud as the platform grows to serve more employees.

Requirements:

Sufficient instances must be available during the migration.
Regular platform upgrades require releasing and re-creating specific instances. Instance re-creation must succeed.

Solution:

Plan required resources: instance types, private pool capacity, and whether to create instances across regions.
Purchase a capacity reservation with Savings Plan and set the effective time based on the project plan.
Start the migration. The capacity reservation takes effect as scheduled, and the private pool capacity ensures successful instance creation.
After the migration, the capacity reservation guarantees resource provisioning during its validity period. During automated upgrades, released instances free up private pool capacity that you can reuse to re-create instances.
For temporary resource needs, use the public pool to leverage cloud elasticity. For stable resources, purchase an immediate capacity reservation.