Help Center/ Image Management Service/ User Guide/ Managing Private Images/ Replicating Images Across Regions
Updated on 2026-06-30 GMT+08:00
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Replicating Images Across Regions

Scenarios

An image is a regional resource. If you want to use a private image in another region, you can replicate it to the target region.

Cross-region image replication is required for system HA typically when your system is deployed in multiple regions. In most cases, ECSs are deployed in multiple regions (including regions outside the Chinese mainland). If you want to clone an ECS across regions, you can replicate its image across the regions and then use the image to create identical ECSs in the target region.
Figure 1 Typical cross-region replication

Video Tutorial

Background

Cross-region replication is applicable to cross-region server deployment or data backup. It is often used together with image sharing for cross-region, cross-account image replication. The following table describes image replication in different scenarios.

Scenario

Description

Procedure

Cross-region replication under the same account

After the replication is complete, a new image is generated in the target region. The new image has an ID that is different from the source image ID.

See this section.

Cross-region, cross-account replication

Replicate the image to the target region and share it with other accounts.

See this section and Sharing Specified Images.

Cross-account replication in the same region

After the replication is complete, the image is shared with the target tenant. The target tenant can use the image (with the same ID as the source image) but the image owner is still the tenant who shared it.

See Sharing Specified Images and Replicating a Shared Image.

Constraints

Table 1 Constraints on cross-region replication under the same account

Item

Description

Image type
  • Only private images can be replicated across regions. If you want to replicate an image of another type (for example, a public image) across regions, you can use the image to create an ECS, use the ECS to create a private image, and then replicate the private image across regions.
    NOTE:
    • A private image cannot be replicated across regions after it is published in KooGallery.
    • If you use a KooGallery image to create an ECS and then use the ECS to create a private image (for example, a Windows image), this private image cannot be replicated across regions.
  • Cross-region replication of full-ECS images is only available for certain regions. You can see on the console if it is available for a given region.

    If a full-ECS image cannot be replicated to a different region, you can use it to create an ECS, use the ECS to create a system disk image and a data disk image, and replicate the images to the destination region.

    A full-ECS image created using an ECS backup can be replicated from the region where they reside to another region, but the replicated full-ECS image cannot be replicated across regions again.

    If cross-region replication of system and data disk images is not available in a region, cross-region replication of full-ECS images is not available in that region, either.

Image size

The size of each image to be replicated across regions cannot exceed 128 GB.

Concurrent replication

Each user can replicate a maximum of five images across regions at a time.

Function

You can select multiple images for cross-region replication at a time. However, you are not allowed to select an ISO image, encrypted image, frozen image, or the image that is being created.

Time

It takes a while to complete a cross-region replication task. The time required for replicating an image across regions depends on the network speed, image size, and number of concurrent tasks.

Permissions

An agency is required for cross-region image replication. This agency must have the permissions for cross-region image replication in the destination region.

For example, if you want to replicate a system or data disk image from region A to region B, the agency must have the permissions of IMS CrossCopyAgencyPolicy in region B. For details about how to create an agency, see Create an Agency.

Billing

When a full-ECS image is replicated across regions, the associated CSBS or CBR backups will also be replicated. Therefore, you will be charged for these backups in the target region.
Figure 2 Cross-region replication of system and data disk images

  • √ indicates replication is supported.
  • × indicates replication is not supported. You can export the desired image and then import it to the target region.
  • - indicates that the source and destination regions are the same.
  • Region adjustment or function open-beta testing may affect cross-region image replication. Existing users are not affected. You can see on the console if cross-region can be performed for a given region.
  • Regions not listed in the figure above do not support cross-region replication of system or data disk images.

Procedure

Cross-region image replication allows you to replicate a single image or multiple images across regions.

  1. Log in to the IMS console.
  2. Locate the row that contains the image to be replicated and choose More > Replicate in the Operation column.
  3. In the displayed Replicate Image dialog box, set the following parameters.
    Figure 3 Replicating an image across regions

    Table 2 Parameters

    Parameter

    Description

    Example Value

    Replication Mode

    Images can be replicated within a region or across regions.

    NOTE:

    This parameter is available only when the current region supports cross-region replication.

    Across Regions

    Name

    Enter a name that is easy to identify. The default image name is in the following format: copy_<name-of-the-region-where-the-source-image-is-located>_<source-image-name>.

    -

    Destination Region

    Select a region from the drop-down list. For details about the supported destination regions, see Figure 2.

    -

    Destination Project

    Select a project from the drop-down list. After you select the destination region, the system automatically displays available projects.

    -

    Target Server Backup Vault

    This parameter is available only for full-ECS images created using CBR. Select a vault for storing backups.

    If no CBR backup vault is available in the destination region, click Create Server Backup Vault to create one. Ensure that you select Replication for Protection Type. For other parameters, see Purchasing a Server Backup Vault. After the vault is created, click to refresh the page and select the vault from the drop-down list box.

    -

    IAM Agency

    Select a created IAM agency for cross-region image replication. The agency must be one created for IMS and granted the required permissions. For details about how to create an IAM agency, see Create an Agency.

    -

    Description

    This parameter is optional. Enter a description for the image.

    -

    Disclaimer

    Read the disclaimer and select I have read and agree to the disclaimer.

    -
  4. Click OK.

    Switch to the destination region. If the image status becomes Normal, the image replication is successful.

  1. Log in to the IMS console.
  2. In the private image list, select the images to be replicated and click Cross-region replication above the list.

    If Cross-region replication is unavailable, the current region does not support cross-region image replication.

  3. In the displayed Replicate Image dialog box, confirm the selected image that can be replicated across regions and specify the required parameters.
    Figure 4 Replicating multiple images across regions

    Table 3 Parameters

    Parameter

    Description

    Example Value

    Destination Region

    Select a region from the drop-down list. For details about the supported destination regions, see Figure 2.

    -

    Destination Project

    Select a project from the drop-down list. After you select the destination region, the system automatically displays available projects.

    -

    Target Server Backup Vault

    This parameter is available only for full-ECS images created using CBR. Select a vault for storing backups.

    If no CBR backup vault is available in the destination region, click Create Server Backup Vault to create one. Ensure that you select Replication for Protection Type. For other parameters, see Purchasing a Server Backup Vault. After the vault is created, click to refresh the page and select the vault from the drop-down list box.

    -

    IAM Agency

    Select a created IAM agency for cross-region image replication. The agency must be one created for IMS and granted the required permissions. For details about how to create an IAM agency, see Create an Agency.

    -

    Description

    This parameter is optional. Enter a description for the image.

    -

    Disclaimer

    Read the disclaimer and select I have read and agree to the disclaimer.

    -
  4. Click OK.

    Switch to the destination region. If the image status becomes Normal, the image replication is successful.

Create an Agency

  1. Log in to the IAM console.
  2. In the navigation pane, choose Agencies.
  3. Click Create Agency.
  4. Set the following parameters:
    • Agency Name: Enter an agency name, for example, ims_copy_image_agency.
      Figure 5 Creating an agency
    • Agency Type: Select Cloud service.
    • Cloud Service: This parameter is available only if you select Cloud service for Agency Type. Select Image Management Service (IMS) from the drop-down list.
    • Validity Period: Select Unlimited.
    • Description: This parameter is optional. You can enter "Delegates with IMS cross-region replication permissions".
  5. Click OK. In the displayed dialog box, click Authorize. Select the permissions to be granted to the agency based on the image type.
    Figure 6 Granting permissions to an agency
  6. Click Next and specify the authorization scope.
    Figure 7 Specifying the authorization scope

    Currently, enterprise projects cannot be used to specify an authorization scope. Only IAM projects can be used.

  7. Click OK.
    Figure 8 New agency

    If the Tenant Administrator or IMS Administrator role is in the permission list, you are advised to delete it to avoid risks caused by excessive permissions. IMS provides fine-grained system policies to allow you to minimize permissions. For example, if the permissions of the agent for cross-region image replication are excessive, you are advised to grant only permissions in the following table.

    Table 4 Permissions required for cross-region image replication

    Scenario

    System-defined Policy

    Cross-region replication of a system or data disk image

    IMS CrossCopyAgencyPolicy

    Cross-region replication of a full-ECS image

    IMS CrossCopyAgencyCBRPolicy
Parent Topic: Managing Private Images