imageId

The ID of the Amazon Machine Image (AMI) used for the instance's current root volume. This value reflects the most recent AMI applied to the instance, including updates made through root volume replacement operations.

This field appears for:

• Instances with root volume replacements through Instance Refresh

• Instances launched with AMI overrides

This field won't appear for:

• Existing instances launched from Launch Templates without overrides

• Existing instances that didn’t have their root volume replaced through Instance Refresh