Purchase a reserved instance - Elastic Compute Service - Alibaba Cloud Documentation Center

This topic describes how to purchase reserved instances in the Elastic Compute Service (ECS) console.

Prerequisites

You are familiar with the deduction rules for reserved instances. For more information, see Deduction rules for reserved instances.

Procedure

Go to the Reserved Instances page.
Go to the Reserved Instances page.
1. Log on to the ECS console.
2. In the left-side navigation pane, choose Deployment & Elasticity > > Reserved Instances.
3. In the top navigation bar, select the region and resource group to which the resource belongs.
Go to the reserved instance buy page.
- If you do not have existing reserved instances in the current region, the Welcome page appears. Click Purchase to go to the reserved instance buy page.
- If you have existing reserved instances in the current region, the reserved instances list page appears. Click Purchase Reserved Instance to go to the reserved instance buy page.

Follow the on-screen instructions to configure the parameters based on your business requirements to purchase a reserved instance. The following table describes the parameters.

Take note of the parameters described in the following table. For information about other parameters, see the instance buy page.

Parameter	Description
Resource Reservation	Reserved: To purchase a zonal reserved instance, set Resource Reservation to Reserved. You must specify a region and a zone. You can use a zonal reserved instance to offset the fees for eligible pay-as-you-go instances in the specified zone, and reserve resources that have matching attributes in the zone. Not Reserved: To purchase a regional reserved instance, set Resource Reservation to Not Reserved. You must specify a region. You can use a regional reserved instance to offset the fees for eligible pay-as-you-go instances in the specified instance family in the specified region, regardless of zone and instance type. However, regional reserved instances do not reserve resources. As a result, you may not be able to offset the fees for pay-as-you-go instances that are matched to a regional reserved instance if the resource inventory is insufficient. Note After you purchase a zonal or regional reserved instance, you can change the reserved instance to a regional or zonal reserved instance at any time. For more information, see Modify the zone of a reserved instance.
Instance Type	Select an instance type. The supported instance types are displayed on the reserved instance buy page. You can select only one instance type for a reserved instance. For information about instance types, see Overview of instance families.
Operating System Platform	Select an operating system platform for the reserved instance. You can use a reserved instance to offset the fees for pay-as-you-go instances only if the images used by the pay-as-you-go instances match the operating system platform of the reserved instance. Reserved instances support Linux and Windows operating system platforms. Important You cannot change the operating system platform of a reserved instance after you purchase the reserved instance. Proceed with caution.
Payment Option	Reserved instances support the All Upfront, Partial Upfront, and No Upfront payment options. For more information, see Payment options.
Quantity	Specify the number of pay-as-you-go instances to which the reserved instance can be applied. The number can be used to: Calculate the computing power of reserved instances. Calculate the amount of resources reserved by zonal reserved instances. For example, if you set Quantity to 2 and Instance Type to ecs.g6.xlarge to purchase a zonal reserved instance, resources for two pay-as-you-go ecs.g6.xlarge instances are reserved.
Term	You must specify a term when you purchase a reserved instance. Note You cannot use expired reserved instances to offset the fees for pay-as-you-go instances. The pay-as-you-go instances are not affected to ensure business continuity.
Effective Time	Now: The reserved instance takes effect immediately after you purchase the reserved instance. Specify Effective Time: The reserved instance takes effect at a specific time after you purchase the reserved instance. For information about how the effective time of a reserved time is related to the time at which billing for the reserved instance starts, see Billing.

Use the reserved instance.
After you purchase a reserved instance, the reserved instance automatically matches pay-as-you-go instances that have specific attributes during the term of the reserved instance without the need for manual intervention. For information about the rules and examples on how reserved instances are used, see Match between reserved instances and pay-as-you-go instances.