» Docker Import Post-Processor

Type: docker-import

The Packer Docker import post-processor takes an artifact from the docker builder and imports it with Docker locally. This allows you to apply a repository and tag to the image and lets you use the other Docker post-processors such as docker-push to push the image to a registry.

» Configuration

The configuration for this post-processor only requires a repository, a tag is optional.

» Required:

  • repository (string) - The repository of the imported image.

» Optional:

  • tag (string) - The tag for the imported image. By default this is not set.

  • changes (array of strings) - Dockerfile instructions to add to the commit. Example of instructions are CMD, ENTRYPOINT, ENV, and EXPOSE. Example: [ "USER ubuntu", "WORKDIR /app", "EXPOSE 8080" ]

» Example

An example is shown below, showing only the post-processor configuration:

{
  "type": "docker-import",
  "repository": "hashicorp/packer",
  "tag": "0.7"
}

This example would take the image created by the Docker builder and import it into the local Docker process with a name of hashicorp/packer:0.7.

Following this, you can use the docker-push post-processor to push it to a registry, if you want.

» Changing Metadata

Below is an example using the changes argument of the post-processor. This feature allows the tarball metadata to be changed when imported into the Docker environment. It is derived from the docker import --change command line option to Docker.

Example uses of all of the options, assuming one is building an NGINX image from ubuntu as an simple example:

{
  "type": "docker-import",
  "repository": "local/centos6",
  "tag": "latest",
  "changes": [
    "USER www-data",
    "WORKDIR /var/www",
    "ENV HOSTNAME www.example.com",
    "VOLUME /test1 /test2",
    "EXPOSE 80 443",
    "LABEL version=1.0",
    "ONBUILD RUN date",
    "CMD [\"nginx\", \"-g\", \"daemon off;\"]",
    "ENTRYPOINT /var/www/start.sh"
  ]
}

Allowed metadata fields that can be changed are:

  • CMD
    • String, supports both array (escaped) and string form
    • EX: "CMD [\"nginx\", \"-g\", \"daemon off;\"]"
    • EX: "CMD nginx -g daemon off;"
  • ENTRYPOINT
    • String
    • EX: "ENTRYPOINT /var/www/start.sh"
  • ENV
    • String, note there is no equal sign:
    • EX: "ENV HOSTNAME www.example.com" not "ENV HOSTNAME=www.example.com"
  • EXPOSE
    • String, space separated ports
    • EX: "EXPOSE 80 443"
  • LABEL
    • String, space separated key=value pairs
    • EX: "LABEL version=1.0"
  • ONBUILD
    • String
    • EX: "ONBUILD RUN date"
  • MAINTAINER
    • String, deprecated in Docker version 1.13.0
    • EX: "MAINTAINER NAME"
  • USER
    • String
    • EX: "USER USERNAME"
  • VOLUME
    • String
    • EX: "VOLUME FROM TO"
  • WORKDIR
    • String
    • EX: "WORKDIR PATH"