Amazon Machine Image (AMI)
- What it is
- Amazon Machine Image — the template EC2 uses to launch an instance.
- Contains the operating system, application server, applications, and launch permissions.
- Where AMIs come from
- AWS-provided (Amazon Linux 2023, Ubuntu, Windows Server).
- AWS Marketplace — vendor images, often with software license included.
- Community images, or custom images you build yourself.
- Why it matters for the exam
- A custom “golden AMI” makes launches repeatable and fast — no configuration at boot.
- AMIs are Regional. Copy an AMI to another Region before launching there.
- One AMI can launch many instance types; the AMI defines software, the instance type defines hardware.
- Not to be confused with
- EBS snapshot — a backup of a single volume. An AMI references snapshots plus the metadata needed to boot.
- AWS CloudFormation — defines the whole stack of resources; an AMI is just the disk image of one instance.