packer/website/source/docs/builders/docker.html.markdown

layout
docs

Docker Builder

Type: docker

The Docker builder builds Docker images using Docker. The builder starts a Docker container, runs provisioners within this container, then exports the container for re-use.

The Docker builder must run on a machine that supports Docker.

Basic Example

Below is a fully functioning example. It doesn't do anything useful, since no provisioners are defined, but it will effectively repackage an image.

{
  "type": "docker",
  "image": "ubuntu",
  "export_path": "image.tar"
}

Configuration Reference

All configuration options are currently required.

• export_path (string) - The path where the final container will be exported as a tar file.

• image (string) - The base image for the Docker container that will be started. This image will be pulled from the Docker registry if it doesn't already exist.

Dockerfiles

This builder allows you to build Docker images without Dockerfiles. If you have a Dockerfile already made, it is simple to just run docker build manually.

With this builder, you can repeatably create Docker images without the use a Dockerfile. You don't need to know the syntax or semantics of Dockerfiles. Instead, you can just provide shell scripts, Chef recipes, Puppet manifests, etc. to provision your Docker container just like you would a regular machine.