This topic describes how to merge reserved instances. If traffic to your instances increases, you can merge multiple reserved instances into a single reserved instance to match larger pay-as-you-go instances. For ease of description, the reserved instance to be merged is referred to as the original reserved instance. The resulting merged reserved instance is referred to as the target reserved instance.

Prerequisites

  • The original reserved instances are purchased with the same currency.
  • The original reserved instances are in the Active state.
  • The original reserved instances belong to the same region if they are regional reserved instances. The original reserved instances belong to the same zone if they are zonal reserved instances.
  • The operating system and the end time of the original reserved instances are the same.
    Note The end time of a reserved instance is determined when you purchase the reserved instance, and is not necessarily the time when the reserved instance becomes inactive. For example, after you merge the reserved instances, the original reserved instances become inactive. However, the end time of the original reserved instances remains unchanged.
  • No ongoing requests for splitting, merging, or modifying reserved instances exist.

Background information

Take note of the following limits when you merge reserved instances:
  • 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 number of pay-as-you-go instances that the target reserved instance can be applied to cannot exceed 100.
  • The total computing power of the target reserved instance must be equal to that of the original reserved instances, as shown in the following figure. For more information about computing power, see Match between reserved instances and pay-as-you-go instances.Merge reserved instances
  • The instance type used by the target reserved instance must exist. For example, you cannot obtain an ecs.g5.5xlarge reserved instance because the ecs.g5.5xlarge instance type is not included in the g5 instance family, as shown in the following figure.The target instance type must exist

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 Merge in the Actions column.
  4. In the Merge Reserved Instances pane that appears, select the reserved instances that you want to merge with the current reserved instance. Set the name, instance type, and instance quantity for the target reserved instance.
  5. Click OK.

Result

After you submit the merging request, the original reserved instances enter the Updating state, and the target reserved instance in the Creating state is displayed. You cannot cancel the ongoing request for merging reserved instances. If you want to roll back the reserved instances, you can split the merged reserved instance to obtain the original reserved instances.

After the request for merging reserved instances is processed, you can obtain one of the following results:
  • If the reserved instances are merged:
    • The original reserved instances enter the Inactive state and expire at the top of the hour when they are merged. The prices become USD 0.
    • The target reserved instance enters the Active state and takes effect at the top of the hour when the original reserved instance are merged. If the target reserved instance is a zonal reserved instance, the type of resources reserved will also be updated automatically.
    • If the target reserved instance matches pay-as-you-go instances, the billing discount provided by the reserved instance is applied to the matched pay-as-you-go instances starting from the hour when the target reserved instance takes effect.
  • If the original reserved instances fail to be merged, they remain active.
Assume that you merged two ecs.g5.xlarge regional reserved instances into an ecs.g5.2xlarge regional reserved instance at 08:30 of May 29, 2020. The following figure shows the time when the original reserved instances expire and the time when the target reserved instance takes effect.The time when the merging takes effect