AMIs

An AMI

Expands to Amazon Machine Image
Is a configuration detail
provides information required to launch an instance.
Can launch multiple instances from a single AMI if multiple instances with same configuration is needed.
Use different AMIs to launch instances with different configurations.

An AMI includes

Single or multiple EBS snapshots
for instance-store-backed AMIs, template for root volume of instance is stored (like OS, application server and software applications).
Launch permissions controlling which AWS accounts can use AMI to launch instances.
A block device mapping specifying volumes to attach to instance when it’s launched.

AMI Types based on characteristics:

Region
Operating system
Architecture (32-bit or 64-bit)
Launch Permissions
- public – all AWS accounts has launch permissions from owner
- explicit – specific AWS accounts has launch permissions from owner
- implicit – Only owner has implicit launch permissions.
Storage for the Root Device
- Backed by Amazon EBS – root device for an instance launched from the AMI is an Amazon EBS volume created from an Amazon EBS snapshot.
- Backed by instance store- root device for an instance launched from AMI is an instance store volume created from a template stored in Amazon S3.

Sharing AMIs

Shared AMI is an AMI that a developer created and made available for other developers to use.
Using shared AMI at own risk
encrypted volumes AMIs cannot be made public
Capability for AMI sharing with AWS accounts without making it public
Sharing AMI by AWS CLI, can be done by modify-image-attribute command
Can also create a bookmark that allows a user to access AMI and launch an instance in their own account.

Sharing an AMI (Console)

Open the Amazon EC2 console at https://console.aws.amazon.com/ec2/.
In the navigation pane, choose AMIs.
Select AMI in the list, and then choose Actions, Modify Image Permissions.
Enlist the AWS account number to share AMI with, in AWS Account Number field, then choose Add Permission.

AMI sharing Guidelines