An Amazon Machine Image (AMI) provides the information required to launch an instance, which is a virtual server in the cloud. You specify an AMI when you launch an instance, and you can launch as many instances from the AMI as you need.
An AMI includes the following:
A template for the root volume for the instance (for example, an operating system, an application server, and applications)
Launch permissions that control which AWS accounts can use the AMI to launch instances
A block device mapping that specifies the volumes to attach to the instance when it's launched
The following diagram summarizes the AMI lifecycle. After you create and register an AMI, you can use it to launch new instances. (You can also launch instances from an AMI if the AMI owner grants you launch permissions.) You can copy an AMI to the same region or to different regions. When you are finished launching instance from an AMI, you can deregister the AMI.
You can search for an AMI that meets the criteria for your instance. You can search for AMIs provided by AWS or AMIs provided by the community. For more information, see AMI Types and Finding a Linux AMI.
When you are connected to an instance, you can use it just like you use any other server. For information about launching, connecting, and using your instance, see Amazon EC2 Instances.
You can customize the instance that you launch from a public AMI and then save that configuration as a custom AMI for your own use. Instances that you launch from your AMI use all the customizations that you've made.
The root storage device of the instance determines the process you follow to create an AMI. The root volume of an instance is either an Amazon EBS volume or an instance store volume. For information, see Amazon EC2 Root Device Volume.
To help categorize and manage your AMIs, you can assign custom tags to them. For more information, see Tagging Your Amazon EC2 Resources.
After you create an AMI, you can keep it private so that only you can use it, or you can share it with a specified list of AWS accounts. You can also make your custom AMI public so that the community can use it. Building a safe, secure, usable AMI for public consumption is a fairly straightforward process, if you follow a few simple guidelines. For information about how to create and use shared AMIs, see Shared AMIs.
You can purchase an AMIs from a third party, including AMIs that come with service contracts from organizations such as Red Hat. You can also create an AMI and sell it to other Amazon EC2 users. For more information about buying or selling AMIs, see Paid AMIs.
You can deregister an AMI when you have finished with it. After you deregister an AMI, you can't use it to launch new instances. For more information, see Deregistering Your AMI.
The Amazon Linux AMI is a supported and maintained Linux image provided by AWS. The following are some of the features of Amazon Linux:
A stable, secure, and high-performance execution environment for applications running on Amazon EC2.
Provided at no additional charge to Amazon EC2 users.
An Amazon EBS-backed, PV-GRUB AMI that includes Linux 3.4, AWS tools, and repository access to multiple versions of MySQL, PostgreSQL, Python, Ruby, and Tomcat.
Updated on a regular basis to include the latest components, and these updates are also made available in the yum repositories for installation on running instances.
Includes packages that enable easy integration with AWS services, such as the Amazon EC2 API and AMI tools, the Boto library for Python, and the Elastic Load Balancing tools.
For more information, see Amazon Linux.