This topic provides answers to some frequently asked questions (FAQ) about the lifecycle of Elastic Compute Service (ECS) images. Operations such as creating an image, copying an image, sharing an image, and deleting an image may change the lifecycle of the images.

FAQ about creating images

FAQ about copying images

FAQ about encrypting images

FAQ about sharing images

FAQ about importing images

FAQ about exporting images

FAQ about deleting images

Can I use a data disk snapshot to create a custom image?

No, data disk snapshots cannot be used to create custom images. Only system disk snapshots can be used to create custom images. However, you can add data disk snapshots when you use a system disk snapshot to create a custom image. For more information, see Create a custom image from a snapshot.

Where do I view the progress of the image creation task when I create a custom image from an instance? How long does it take to create the custom image?

You can view the progress of an image creation task on the Images page of the ECS console. The amount of time required to create a custom image from an instance varies based on the total size of the disks on the instance. You must wait until a snapshot is created for each disk before you can use the image. For more information, see Create a custom image from an instance.

When do I need to copy a custom image?

Custom images are regional resources. Each custom image can be used only within a single region. You can create copies of custom images and use the copies to perform the following operations:
  • Deploy applications that are hosted on ECS instances to multiple regions.
  • Migrate ECS instances to other regions.
  • Use custom images across multiple regions.
  • Change the encryption status of custom images, encrypt system disks, or encrypt operating system data.
You can copy a custom image from one region to another region within the same account. For more information, see Copy an image.

Which images can be copied?

Only custom images can be copied. Public images, Alibaba Cloud Marketplace images, and images that are shared by other accounts cannot be copied.

How long does it take to copy an image?

When you copy a custom image across regions, the image file is transmitted from one region to another. The amount of time it takes to copy a custom image depends on the network transmission speed and the number of concurrent transmission tasks in the queue.

If you want to copy a large image (such as an image that is larger than 2 TiB in size) across regions, you can copy the associated snapshots to a destination region and then create a custom image from the snapshot copies in the destination region. This procedure is faster than directly copying the image. For more information, see Copy a snapshot and Create a custom image from a snapshot. For information about snapshot billing, see Snapshots.

Can I copy a custom image that is derived from an Alibaba Cloud Marketplace image across regions?

If an Alibaba Cloud Marketplace image is available in a destination region, you can copy custom images that are derived from the Alibaba Cloud Marketplace image to the destination region. If an Alibaba Cloud Marketplace image is not available in a destination region, the error message shown in the following figure appears when you copy a custom image that is derived from the Alibaba Cloud Marketplace image to the destination region.

Copy a custom image that is derived from an Alibaba Cloud Marketplace image

How many images can be shared to me?

Up to 100 images can be shared to you. You can go to the ECS console to view and increase image quotas. For more information, see View and increase resource quotas.

How many users can an image be shared to?

An image can be shared to up to 50 users. If you want to increase this image quota, submit a ticket.

I have accounts on different Alibaba Cloud sites. Can I share images between these accounts?

Yes, images can be shared between your accounts on the China site (aliyun.com), International site (alibabacloud.com), and Japan site (jp.alibabacloud.com), except for custom images that are derived from Alibaba Cloud Marketplace images. The fees for custom images that are derived from Alibaba Cloud Marketplace images vary based on the site. You cannot share these images across the sites.

What are the risks when I use a shared image?

  • Shared images pose risks of data leakage and software theft. Before you share an image to other accounts, check whether the image contains sensitive or important data. After an image is shared to other accounts, the accounts can use the shared image to create ECS instances, which can then be used to create more custom images. During this process, data can be repeatedly spread. This poses risks of data being disclosed beyond your original intentions.
  • Alibaba Cloud does not guarantee the integrity and security of images that are shared by other accounts. We recommend that you select only images that are shared by trusted accounts. When you create an ECS instance from a shared image, you must log on to the ECS instance to check the security and integrity of the image.
  • The image owner can check how the image is shared and delete the image. After a shared image is deleted by the image owner, the system disks of the instances that use the image cannot be re-initialized.

After an account shares an image to me, can I share this image to another account?

No, you cannot directly share the image to other accounts. However, you can copy the shared image to create a custom image and then share the custom image to other accounts.

How do I share an image to another account in a different region?

You can share an image to another account and then copy the shared image to a destination region. You can also copy the image to the destination region and then share the image copy to the account. For more information, see Copy an image and Share a custom image.

Do the system disks of ECS instances support Key Management Service (KMS) encryption? How do I use Terraform or Packer to encrypt the system disks?

  • Yes, the system disks of ECS instances can be encrypted by using default service customer master keys (CMKs) or custom CMKs in KMS. For more information, see Encrypt a system disk.
  • In Packer, you can set the image_encrypted parameter to specify whether to encrypt a system disk. For more information, see Alicloud Image Builder.
  • In Terraform, you can set the encrypted parameter to specify whether to encrypt a system disk. For more information, see alicloud_disks.

What are the requirements when you use the Copy and Encrypt feature to copy an image?

  • You must activate KMS. For more information, see Activate KMS.
  • You must set Copy Mode to Copy and Encrypt.
  • If you want to use a custom CMK, you must create the CMK in KMS beforehand. For more information, see Create a CMK.

What permissions are required to share an encrypted image?

Before you can share an encrypted image to other Alibaba Cloud accounts or within your organization based on resource directories, you must use Resource Access Management (RAM) to create a RAM role named AliyunECSShareEncryptImageDefaultRole and grant the required permissions to the role. For more information, see Share an encrypted custom image.

Where do I view the progress of an image import task? How long does it take to import an image?

To view the progress of an image import task that is performed in a specific region, select the region and go to the Images or Task Logs page in the ECS console.

The amount of time required to import an image varies based on the image size and the number of ongoing concurrent import tasks. For more information, see Import custom images.

I created instances from an imported bring-your-own-license (BYOL) image. How do I purchase licenses that are provided by Alibaba Cloud for the instances when their license subscriptions expire?

You can replace the BYOL image with an Alibaba Cloud image by replacing the operating system of the instances.
  • For Windows Server operating systems, you can use Alibaba Cloud public images. For information about Alibaba Cloud public images, see Overview.
  • You can obtain SQL Server and Red Hat images from Alibaba Cloud Marketplace. For more information, see Alibaba Cloud market mirror images.

Can I use an internal URL that is provided by Object Storage Service (OSS) to import custom images?

No, internal URLs provided by OSS cannot be used to import custom images. To import an image, you must use the public URL generated when you share the image object in OSS. If you use an internal URL that is provided by OSS to import an image, an error is reported.

How do I convert ISO files to image formats that are supported by ECS?

An ISO file must be converted to an image format that is supported by ECS before the file can be imported to ECS.
  1. Use tools such as VirtualBox to create an image based on an ISO file on-premises.
  2. Convert the image format to a format that is supported by ECS, such as RAW, VHD, and QCOW2.
For more information, see Import custom images.

How do I upload on-premises image files to ECS instances?

For more information, see Import custom images.

What permissions are required to upload image files to OSS?

  • If you are using an Alibaba Cloud account, you can directly upload image files to OSS. For more information, see Upload image files to OSS.
  • If you are using a RAM user, ask the owner of the corresponding Alibaba Cloud account to grant the RAM user operation permissions on OSS buckets. For more information, see Grant permissions for different scenarios.

How do I download image files to my computer?

You can use the image export feature to export image files to your computer. For more information, see Export a custom image.

Can an image exported from ECS start on other platforms?

Images exported from ECS may not start as expected on other platforms. You can attach the disks that are contained in the images to obtain data.

Can I delete a custom image that I used to create ECS instances or shared? What is the impact of deleting the image?

You can only select Forcibly Delete in the Delete Image dialog box to forcefully delete the image.

For example, you share Image M to Alibaba Cloud Account A. If you delete the image, the following situations occur:
  • Account A can no longer query Image M by using the ECS console or by calling ECS API operations.
  • Account A can no longer use Image M to create ECS instances or replace system disks.
  • If Account A created ECS instances from Image M, the system disks of the instances can no longer be re-initialized.
For more information, see Delete a custom image.

Why am I prompted with a message similar to "The specified image cannot be deleted because it is associated with instances" when I attempt to delete an image?

The image may have been used to create ECS instances. To delete this image, you must select Forcibly Delete. After an image is forcefully deleted, instances created from the image are still available, but the disks of the instances cannot be re-initialized. For more information, see Re-initialize a system disk. For more information, see Delete a custom image.