What Is an Amazon Machine Image?
Benefits of Amazon Machine Images
An AMI provides speed, efficiency, and conformity of deployment. Because all the necessary elements are bundled and preconfigured together, including permissions, an AMI can be spun up on an Amazon EC2 VM ready to go. The capabilities will be the same across VMs deployed using the same AMI, enabling rapid, predictable scaling of a generic service. No manual installation of software dependencies will be required.
Due to its behavior as a virtual appliance, there can be a considerable cost benefit from using an AMI. A single instance can be deployed with a predictable price and then scaled up by adding further instances with the same linear cost increase as requirements grow. There is no need to over-provision just in case of future demand.
Deploying via an AMI can also offer flexibility, with options often available for different operating systems, including Windows, Linux, and UNIX. Additional services may also be available to extend functionality based on the same generic core image.
Examples of Amazon Machine Images
1. Public
2. Paid
3. Shared
How an Amazon Machine Image Works
Deploying an AMI usually starts with the AWS Marketplace, which provides a searchable storefront through which an Image that delivers the functionality required can be found. The user can then subscribe to the AMI for free or via various payment methods if it’s a premium image. An appropriate Amazon EC2 instance in a preferred region will be simultaneously deployed to host the AMI, with its costs rolled into a single regular fee.
The AMI and the VM hosting it are deployed together, providing a seamless series of steps that streamline the process. The VM will be spun up, the image copied across, and the configuration completed in a matter of minutes. Even with Shared AMIs not deployed via the AWS Marketplace, the developer can provide a similar process that combines the image and VM into one configuration sequence.