When your workload changes, such as being distributed across smaller instances or consolidated onto larger ones, you can split, merge, or modify existing reserved instances. This flexibility allows you to better match pay-as-you-go instances of various types and in different zones. As a result, you can continue to receive discounts, meet new computing demands, and optimize your cloud resource costs.
For clarity, a reserved instance that is being split, merged, or modified is called a source reserved instance. The resulting new reserved instance is called a destination reserved instance.
Prerequisites
Before you split, merge, or modify a reserved instance, make sure that:
The reserved instance is in the Active state.
No split, merge, or modification request is being processed.
Split a reserved instance
If your workload is distributed across multiple smaller pay-as-you-go instances, you can split a single reserved instance into multiple reserved instances with lower computing power. This improves the match with your pay-as-you-go instances and accommodates workload distribution.
Limitations
The following limitations apply when you split a reserved instance:
Reserved instances of the gn6i and t5 instance families cannot be split.
The destination reserved instances must have the same reservation type, payment type, expiration date, region or zone, and instance type prefix as the source reserved instance.
The total computing power of the destination reserved instances must equal the computing power of the source reserved instance.
NoteThe computing power of a reserved instance = normalization factor of the instance type × Number of instances. To find the normalization factor for different instance types, see View normalization factors.
Procedure
On the Reserved Instances page, find the reserved instance that you want to split. In the Actions column, click the
icon and select Split.In the Split Reserved Instance dialog box, configure the name, instance type, and quantity for each destination reserved instance.
Click OK. You can then view the operation results.
Merge reserved instances
If your workload is concentrated on a few large instances, you can merge multiple reserved instances into a single one with greater computing power. This helps you cover these large pay-as-you-go instances more effectively.
Limitations
The following limitations apply when you merge reserved instances:
Reserved instances of the gn6i and t5 instance families cannot be merged.
The source reserved instances that you select for merging must have the same reservation type, payment type, expiration date, region or zone, and instance type prefix.
The number of instances in the destination reserved instance must be less than or equal to 100.
The computing power of the destination reserved instance must equal the sum of the computing power of the source reserved instances.
NoteThe computing power of a reserved instance = normalization factor of the instance type × Number of instances. To find the normalization factor for different instance types, see View normalization factors.
Procedure
On the Reserved Instances page, find one of the reserved instances that you want to merge. In the Actions column, click the
icon and select Merge.In the Merge Reserved Instances dialog box, select the other source reserved instances and then configure the name, instance type, and quantity for the destination reserved instance.
Click OK. You can then view the operation results.
Modify a reserved instance's zone
If a reserved instance's current zone becomes unsuitable due to business changes, such as expansion or migration, you can modify the zone to better match your pay-as-you-go instances.
On the Reserved Instances page, find the reserved instance that you want to modify and click Modify in the Actions column.
In the Modify Reserved Instance dialog box, configure the Name and Region/Zone.
You can only change the Region/Zone within the same region. The following modifications are supported:
For a zonal reserved instance:
You can change it to another zone within the same region.
You can change its scope from zonal to regional within the same region.
For a regional reserved instance: You can change its scope from regional to zonal within the same region.
NoteIf the target zone has insufficient inventory for the specified instance type, you cannot select that zone.
Click OK. You can then view the operation results.
Operation results
After you submit a request, the source reserved instance enters the Updating state, and the new destination reserved instance appears with a status of Creating.
You cannot cancel a request that is in progress. To roll back a change, you must perform the reverse operation. For example, to undo a split, you can merge the resulting reserved instances.
After the request is processed:
If the operation is successful:
Source reserved instance
Enters the Inactive state. The deactivation becomes effective at the start of the hour in which the operation is completed, and its price is set to 0 USD.
You can view only historical bills for the source reserved instance.
Destination reserved instance
Enters the Active state. The activation becomes effective at the start of the hour in which the operation is completed.
For example, if you split a zonal reserved instance of the
ecs.g6.2xlargeinstance type (with capacity reservation) into two zonal reserved instances of theecs.g6.xlargeinstance type (with capacity reservation) at 20:30 on May 28, 2024, the source reserved instance becomes Inactive at 20:00 on May 28, 2024, and the destination reserved instances become Active at 20:00 on May 28, 2024.For a zonal reserved instance, the associated capacity reservation is also automatically updated.
If the destination reserved instance successfully matches a pay-as-you-go instance, the discount is applied to your bill within the same hour.
If the operation fails, the source reserved instance remains Active and its function is unaffected.