We've recently migrated a system off of a set of EC2 instances, and now wish to retire those EC2 instances, first by creating an AMI of and then terminating each EC2 instance.
Over time, we've created a number of EBS snapshots of the volumes attached to the EC2 instances as a part of our maintenance strategy.
Will the EBS snapshots referenced by the AMIs we create be independent of the maintenance EBS snapshots? In other words, will the EBS snapshots referenced by the AMIs have pointers back to the most recent maintenance EBS snapshots, or will they reference the relevant blocks independently of the maintenance EBS snapshots?
Ultimately, I'm trying to determine whether, once the AMIs are created, if it is useful or worthwhile to delete the maintenance EBS snapshots from a cost and management overhead perspective.
When you create an AMI it creates a new set of snapshots, one for each EBS. And these snapshots can't be deleted until you delete the AMI first. So yes, they are independent and you can delete all your other "maintenance" snapshots.
Hope that helps :)
EBS snapshots are EBS snapshots. Those created by AMI images aren't "special" in any way.
You can safely delete the older EBS snapshots for the same EBS volumes and the data in your recent snapshots will be preserved.