A company copies a custom AMI from us-east-1 to eu-west-1 so it can launch instances there. A few weeks later, they deregister the original AMI in us-east-1 because it's no longer needed. What happens to the copy in eu-west-1?
- The copied AMI in eu-west-1 is entirely independent, with its own distinct AMI ID; deregistering the original AMI in us-east-1 has no effect on it
- Deregistering the source AMI in us-east-1 automatically deregisters the copy in eu-west-1 too, since copies stay linked to their source
- The copy in eu-west-1 shares the exact same AMI ID as the original in us-east-1, since AMI IDs are global across Regions
- The copy cannot be used to launch instances until the original AMI in us-east-1 is deregistered first
Why A? And why not the others?
Correct answer: A. The copied AMI in eu-west-1 is entirely independent, with its own distinct AMI ID; deregistering the original AMI in us-east-1 has no effect on it
Copying an AMI to another Region produces an identical but fully independent target AMI with its own distinct AMI ID in that destination Region, and each of its supporting EBS snapshots is likewise copied to its own distinct target snapshot; because the copy is independent, changing or deregistering the source AMI afterward has no effect on the copy, and the reverse is true as well. The option claiming deregistering the source automatically deregisters the copy invents a dependency between source and copy that doesn't exist; once the copy completes, the two are managed entirely separately. The option claiming the copy shares the same AMI ID as the original is wrong because AMI IDs are Region-specific identifiers, not globally unique across Regions, so the copy always receives its own new ID in the destination Region. The option requiring the original to be deregistered before the copy can be used has the relationship backwards; the copy is independently usable as soon as its own status becomes available, regardless of what later happens to the source.
Source: AWS EC2 documentation: Copy an Amazon EC2 AMI — cross-Region copy creates an independent AMI