This topic provides answers to some frequently asked questions (FAQ) about the relationships between Elastic Compute Service (ECS) images and snapshots, and the relationships between images and instances.
- Is the lifecycle of an image the same as that of its associated ECS instance?
- What are the relationships and differences between images and snapshots?
- What happens to a custom image when the instance from which the image was created is released?
- If an image was manually created from an ECS instance, can I retrieve instance data after the instance is released on expiration?
- Can a custom image created from a subscription instance be used to create a pay-as-you-go instance?
Is the lifecycle of an image the same as that of its associated ECS instance?
The lifecycle of an image is the same as that of its associated ECS instance. When you create an instance, you must select an image. The image uses the same billing method as the instance. The billing method can be subscription or pay-as-you-go.
What are the relationships and differences between images and snapshots?
- When you create a custom image from an instance, ECS creates a snapshot for each disk (system disk and data disks) of the instance. The created custom image consists of the snapshots of all disks of the instance. For more information, see Create a custom image from an instance.
- When you delete a custom image, you can determine whether to delete the corresponding snapshot. When you delete a snapshot, the system checks whether the snapshot is associated with an image. If the snapshot is associated with the an image, the snapshot cannot be deleted before the image is deleted. For more information, see Delete a custom image and Delete a snapshot.
- You can use a system disk snapshot to create a custom image. For more information, see Create a custom image from a snapshot.
Item | Image | Snapshot |
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Nature | Images provide operating systems, initialization data of applications, and pre-installed software for ECS instances. | A snapshot is a point-in-time backup of a disk. |
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What happens to a custom image when the instance from which the image was created is released?
After an instance is manually released or is automatically released when it expires, the custom images created from the instance and the instances created from the custom images are not affected.
If an image was manually created from an ECS instance, can I retrieve instance data after the instance is released on expiration?
- Create an instance from the created image. For more information, see Create a custom image from an instance.
- Use the created image to replace the system disk of an existing instance. For more information, see Replace the operating system (system disk) of an instance.
- The image must be in the same region as the existing instance.
- Maintain a sufficient balance in your account balance to prevent data from being released due to snapshot deletion 15 days after the instance expires or after a payment becomes overdue for the instance. For more information, see Snapshots.
Can a custom image created from a subscription instance be used to create a pay-as-you-go instance?
Yes, a custom image created from a subscription instance can be used to create a pay-as-you-go instance. The use of custom images has nothing to do with the billing methods of instances.