Use a system disk snapshot to create a custom image to quickly replicate the environment of an ECS instance - Elastic Compute Service

You can create a custom image from a system disk snapshot of an existing ECS instance. The custom image contains the operating system, installed software, configurations, and data from the source ECS instance. You can use the custom image to create ECS instances that have the same environment as the original instance, which lets you quickly replicate the system environment. This topic describes how to create a custom image from a system disk snapshot.

Prerequisites

You have created a system disk snapshot. For more information, see Create a snapshot.
You have deleted sensitive data from the snapshot to prevent security risks.

Considerations

Before you use a snapshot to create a custom image, take note of the following items:

Item	Description
Region restrictions	The snapshot and the custom image to be created must be in the same region. If you want to use an image across regions, you can first create a custom image and then copy the custom image across regions.
Snapshot restrictions	Only system disk snapshots can be used to create custom images. Data disk snapshots cannot be used to create custom images. Shared snapshots cannot be used to create custom images. Encrypted and non-encrypted snapshots can be used to create custom images. A custom image created from an encrypted snapshot is encrypted by default, and its encryption key is the same as the key of the source snapshot.
Billing	You are charged for snapshot storage. For more information, see Snapshot billing.
Creation period	The amount of time required to create an image varies based on the sizes of disks. You must wait until the snapshot of each disk is created before you can use the image.
Other considerations	If the ECS instance from which a snapshot was created expires or is released, the custom images created from the snapshot and the ECS instances created from the images are not affected.

Procedure

You can use a system disk snapshot to create a custom image on the Images page, the instance details page, or the Snapshots page. This topic uses the Snapshots page as an example.

Go to ECS console - Snapshots.
In the top navigation bar, select the region and resource group of the resource that you want to manage.
On the Disk Snapshot tab, find the snapshot with a Disk Attribute of System Disk, and in the Actions column, click Create Custom Image.

In the Create Custom Image dialog box, specify the following configurations.

Parameter	Description	References
Image Name	Enter a name for the custom image.	Not applicable
(Optional) Image Check	The image check feature checks whether imported custom images are valid and whether the images can be used to create full-featured ECS instances. By default, Check After Creation is selected. The image check feature immediately checks the custom image after the image is created. After the image check is completed, you can view the check details in the Check Result column of the custom image list. If an item needs to be repaired, you can use the ACS-ECS-RepairImage public template of CloudOps Orchestration Service (OOS) to repair the item with a single click or manually repair the item based on the suggestions in the image details. Note The image check feature is supported only by some operating systems. For information about the operating systems that do not support this feature, see Check and repair custom images.	Check and repair custom images
(Optional) Image Family	You can select an image family when you create a custom image. Custom images that belong to an image family can be set to be deprecated or restored to be active to allow seamless image updates and rollbacks.	Image family
(Optional) Snapshot Configuration	Select Add Data Disk and click Add. Then, select a data disk snapshot ID. After you add data disks, the custom image created from the snapshot will contain the same number of data disks. If you do not select a data disk snapshot ID, an empty data disk is created. The default size of the data disk is 5 GiB. If you select a data disk snapshot ID, the new data disk has the same capacity as the snapshot.	Create a disk from a snapshot
Snapshot Billing	If an automatic release time is configured for the snapshot, you must select I Have Read The Snapshot Billing Notice "Snapshot Billing". Important An automatic release time is configured for the snapshot that you selected. To ensure that the snapshot can be automatically released as scheduled, you must manually delete the related images created from this snapshot before the snapshot expires. If the related images are not deleted, the snapshot cannot be automatically released and continues to incur fees.	Snapshot billing
(Optional) Image Description	Enter a description for the custom image.	Not applicable
(Optional) Tag	Select a tag. Optional: This parameter is optional in most scenarios. Required: This parameter is required when you use a RAM user to which a RAM policy that enforces tag binding is attached. Otherwise, a permission error is reported.	Tags
(Optional) Resource Group	Select a resource group to manage the custom image that you want to create from the perspectives of usage and permissions.	Resource groups

Click OK. Wait for the image to be created.