First Image with Docker

This is the hands-on lab for Section 4 of Packer 101. You write a Docker builder template that pulls ubuntu:24.04, runs a shell provisioner that writes a marker file, commits the container to a local image, and tags it for easy proof and cleanup. You intentionally break the provisioner, read the build log, and fix it before a successful bake. No cloud account is required.

You will:

• Confirm Packer 1.16.0 and Docker Engine on the lab host
• Write docker-ubuntu.pkr.hcl with required_plugins docker ~> 1.1, commit =

true, and a shell provisioner

• Run packer init, fmt, and validate, then recover from a deliberate

provisioner failure

• Build the image, prove it with docker images and docker run, then remove

the local tag