Registers an AMI. When you're creating an AMI, this is the final step you must complete before you can launch an instance from the AMI. For more information about creating AMIs, see Create your own AMI in the Amazon Elastic Compute Cloud User Guide.

For Amazon EBS-backed instances, CreateImage creates and registers the AMI in a single request, so you don't have to register the AMI yourself. We recommend that you always use CreateImage unless you have a specific reason to use RegisterImage.

If needed, you can deregister an AMI at any time. Any modifications you make to an AMI backed by an instance store volume invalidates its registration. If you make changes to an image, deregister the previous image and register the new image.

Register a snapshot of a root device volume

You can use RegisterImage to create an Amazon EBS-backed Linux AMI from a snapshot of a root device volume. You specify the snapshot using a block device mapping. You can't set the encryption state of the volume using the block device mapping. If the snapshot is encrypted, or encryption by default is enabled, the root volume of an instance launched from the AMI is encrypted.

For more information, see Create a Linux AMI from a snapshot and Use encryption with Amazon EBS-backed AMIs in the Amazon Elastic Compute Cloud User Guide.

Amazon Web Services Marketplace product codes

If any snapshots have Amazon Web Services Marketplace product codes, they are copied to the new AMI.

Windows and some Linux distributions, such as Red Hat Enterprise Linux (RHEL) and SUSE Linux Enterprise Server (SLES), use the Amazon EC2 billing product code associated with an AMI to verify the subscription status for package updates. To create a new AMI for operating systems that require a billing product code, instead of registering the AMI, do the following to preserve the billing product code association:

1. Launch an instance from an existing AMI with that billing product code.

2. Customize the instance.

3. Create an AMI from the instance using CreateImage.

If you purchase a Reserved Instance to apply to an On-Demand Instance that was launched from an AMI with a billing product code, make sure that the Reserved Instance has the matching billing product code. If you purchase a Reserved Instance without the matching billing product code, the Reserved Instance will not be applied to the On-Demand Instance. For information about how to obtain the platform details and billing information of an AMI, see Understand AMI billing information in the Amazon EC2 User Guide.