AWS AMI manifest and content

There are no formal documents that I’m aware of that explain how the images are structured. The details are really self-evident from the existing tools which don’t really obfuscate any of the details.  The details are in the code is in the ec2-bundle-image CLI (90% Ruby and 10% BASH) which actually builds the AMI and manifest file.

Using AMIs on premise

AMIs provide a great way to package your software deployment.  Once this pre-configured 'template' is created some IT folks may want to use it on premise.  The solution to that does this is:
http://www.eucalyptus.com
Details can be found here:
http://www.eucalyptus.com/eucalyptus-cloud/iaas/concepts
Before the AMI can be used on premise, it must be converted to an EMI:
AMI--->EMI before using on premise.

Eucalyptus has support for EC2 instances, EBS, S3, and IAM.  It also has API compatibility.  They just announced support for ELB, Auto Scaling, and CloudWatch.

They are an AWS partner:https://aws.amazon.com/solution-providers/isv/eucalyptus