ami-direct

CLI tool imports a raw disk image as an EBS snapshot and registers it as an EC2 AMI. Uses EBS Direct API.

Context

I built this prototype because local OS image creation had stopped being the slow part. mkosi can build a tailored Linux disk image in a matter of seconds, but pushing those into AWS as AMIs still took several minutes per attempt:

• import-snapshot is reliable and requires very little setup, but was too slow for a tight build-run-debug cycle, sometimes up to 12 minutes even for small images.
• the faster S3 -> tiny EC2 -> EBS -> snapshot¹ path still meant waiting a few minutes after every kernel option or boot script change

The EBS Direct API provides a faster path: stream the disk blocks straight into a snapshot, then register the AMI, typically in tens of seconds.

The tradeoff is cost: PutSnapshotBlock pricing is $0.006 per 1,000 requests, or about 1.2 cents per GiB written.

Usage

Usage: ami-direct [flags] <input-file>

  <input-file> must be a raw disk image

Flags:
  -arch string
        AMI architecture (default "x86_64")
  -description string
        description for the snapshot and AMI
  -name string
        AMI name; also used as the default Name tag
  -no-ami
        only create the snapshot; do not register an AMI
  -no-overwrite
        fail if an AMI with the same name already exists
  -tag value
        tag in Key=Value form; applied to the snapshot and AMI; repeatable
  -workers int
        number of concurrent upload workers (1-20) (default 20)

Footnotes

1. EBS Surrogate as Packer calls it ↩