Purchase a reserved instance

Procedure

1. Go to ECS console - Reserved Instances.

2. In the top navigation bar, select the region and resource group of the resource that you want to manage.

3. Go to the reserved instance purchase page.

   • If you have not purchased a reserved instance in the current region, click Storage Capacity Units on the reserved instance homepage.

   • If you have already purchased a reserved instance in the current region, click Purchase Reserved Instances above the reserved instance list.

4. Configure and purchase the reserved instance by following the on-screen instructions.

   The following table describes key parameters. For other parameters, refer to the on-screen tooltips.

   Parameter	Description
   Resource reservation	Reserved: A zonal reserved instance. You must specify a region and an availability zone. Provides a discount on matching pay-as-you-go instances and reserves capacity for them within a single availability zone. Not Reserved: A regional reserved instance. You only need to specify a region. Provides a discount on matching pay-as-you-go instances across all availability zones in the region. The discount can apply to different instance types within the same instance family. However, capacity is not reserved, and you may need to wait for resources if inventory is low. Note You can convert between zonal and regional reserved instances at any time after purchase. For more information, see Modify the availability zone of a reserved instance.
   Instance Type	Select the instance type to which the discount applies. The available instance types are listed on the page. Each reserved instance applies to only one instance type. For more information about instance types, see Instance families. Note Both reserved instances with and without capacity reservation require sufficient inventory for the selected instance resources. Otherwise, the purchase will fail. You can call the DescribeAvailableResource API operation to check the resource inventory in a specified region or availability zone.
   Operating System	The discount applies only if the operating system of the matching pay-as-you-go instance matches the platform you select. The supported operating system platforms are Linux and Windows. Important The operating system platform cannot be changed after purchase.
   Billing Method	Reserved instances support three payment options: All Upfront, Partial Upfront, and No Upfront. For more information, see Payment options.
   Quantity	The Quantity parameter determines the following: The computing power of the reserved instance. For a zonal reserved instance, the number of instances for which capacity is reserved. For example, if you purchase a reserved instance for the ecs.g6.xlarge instance type with a quantity of 2, capacity is reserved for two ecs.g6.xlarge instances.
   Term	You must specify a term when you purchase a reserved instance. Note When a reserved instance expires, its discount no longer applies to matching pay-as-you-go instances. This change does not affect the running instances or interrupt your services.
   Effective Time	Now: The discount applies immediately after a successful purchase. Specify Effective Time: The discount takes effect at a future time that you specify. For information about the relationship between the effective time and the billing start time of a reserved instance, see Billing rules.

5. Use the reserved instance.

   After a successful purchase, you do not need to manually apply the reserved instance. During its term, the system automatically applies the discount to matching pay-as-you-go instances. For more information about matching rules and for discount examples, see Matching rules for reserved instances.