You can split a single reserved instance into multiple reserved instances to match smaller pay-as-you-go instances. For ease of description, the reserved instance to be split is referred to as the original reserved instance. The resulting reserved instances are referred to as the target reserved instances.

Prerequisites

  • The original reserved instance is in the Active state.
  • No ongoing requests for splitting, merging, or modifying reserved instances exist.

Background information

Note the following limits when you split a reserved instance:
  • Reserved instances of instance types that belong to the t5 instance family cannot be split.
  • You can change the instance type of a reserved instance. The instance family of a reserved instance cannot be changed.
  • You cannot change the zone or region of a reserved instance.
  • The total computing power of the target reserved instances must be equal to that of the original reserved instance, as shown in the following figure. For more information about computing power, see Match between reserved instances and pay-as-you-go instances. Split a reserved instance

Procedure

  1. Log on to the ECS console.
  2. In the left-side navigation pane, choose Instances & Images > Reserved Instances.
  3. On the Reserved Instances page, find the original reserved instance and click Split in the Actions column.
  4. In the Split Reserved Instance pane that appears, set the names, instance types, and quantities of the target reserved instances.
  5. Click OK.

Result

After you submit the splitting request, the original reserved instance enters the Updating state, and the target reserved instances in the Creating state are displayed. You cannot cancel the ongoing request for splitting a reserved instance. If you want to roll back the change made by the splitting operation, you can merge the target reserved instances to obtain the original reserved instance.

After the request for splitting a reserved instance is processed, you can obtain one of the following results:
  • If the reserved instance is split:
    • The original reserved instance enters the Inactive state and expires at the top of the hour when it is split. The price becomes USD 0.
    • The target reserved instances enter the Active state and take effect at the top of the hour when the original reserved instance is split. If the target reserved instances are zonal reserved instances, the type of resources reserved will also be updated automatically.
    • If the target reserved instances match pay-as-you-go instances, the billing discounts provided by these reserved instances are applied to the matched pay-as-you-go instances starting from the hour when the target reserved instances take effect.
  • If the original reserved instance fails to be split, this reserved instance remains active.
Assume that you split the ecs.g5.2xlarge zonal reserved instance into two ecs.g5.xlarge zonal reserved instances at 20:30 of May 28, 2020. The following figure shows the time when the original reserved instance expires and the time when the target reserved instances take effect.The time when the splitting takes effect