Amazon Machine Image (AMI)
- An Amazon Machine Image (AMI) provides the information required to launch an instance.
- AMI comes with various base images Amazon Linux, Ubuntu, Fedora, Red Hat, Windows etc.
- These images can be customized at runtime using EC2 user-data
- AMI allows you to create your own customized image.
- AMI Includes – One or more EBS snapshots for instance-store-backed AMIs, a template for the root volume of the instance (for example, an operating system, an application server, and applications).
- You can launch multiple instances from a single AMI when you need multiple instances with the same configuration.
AMI uses S3 for storing
- When you create your own AMI from the instance it requires space to store and they live in Amazon S3.
- Hence you are charged for the space occupied in S3 for storing S3. So make sure you remove the AMIs which are not in use.
- By default AMIs are private and locked for your account/region. They can be made public and shared with other AWS accounts if required.
Shared AMI behavior
- You can share an AMI with another AWS account.
- Sharing an AMI does not affect the ownership of the AMI.
- You cannot associate your billing product shared by other while again sharing the AMIs to public
- You can share an AMI with specific AWS accounts without making the AMI public. All you need is the AWS account IDs.
Benefits of using AMI
- AMIs comes with pre-installed OS and other packages
- When you use AMI to create instance you don’t need to use user-data for startup automation every time
- Helps in deploying set of instances in one go faster than manually creating EC2 instances
- Public AMIs help you reduce time in commissioning instances
You cannot use ADDS in AMIs as replicating the DC with same domain in multiple locations will be of no use.