Tarball Post Processor for Packer

This post-processor for Packer creates a tarball of the root filesystem using Guestfish. The resulting image is suitable for deploying OpenVZ containers.

The Qemu builder is used in favor of a writing a separate OpenVZ builder for a few reasons:

• Preference building from an ISO over an existing template
• Qemu does not require a proprietary kernel
• The Qemu builder is stable, and writing post-processors is relatively easy
• Having a tarball of the filesystem potentially has uses outside of OpenVZ

Requirements

• Packer 0.8.x+
• Guestfish (and libguestfs)
• Qemu (preferrably with KVM acceleration)

Installation

First, download and install the plugin:

$ go get github.com/DavidWittman/packer-post-processor-tarball

Then, move the binary from $GOPATH/bin/packer-post-processor-tarball to one of three locations:

• The directory where packer is, or the executable directory
• ~/.packer.d/plugins/ (Unix) or %APPDATA%/packer.d/plugins (Windows)
• The current working directory

Usage

Once the packer-post-processor-tarball binary is in a directory which is discoverable by Packer, you can add this post-processor to your template as follows:

{
  "post-processors": ["tarball"]
}

Configuration

Here are all of the available configuration options (and their defaults) for this post-processor. Keys beginning with an underscore are comments.

{
  "post-processors": [
    {
      "type": "tarball",

      "_comment": "The directory to write artifacts to",
      "output": "packer_{{.BuildName}}_tarball",

      "_comment": "Filename to use for the artifact. `tarball_extension` will be appended to the end",
      "tarball_filename": "packer_{{.BuildName}}",

      "_comment": "Filename extension to use",
      "tarball_extension": ".tar.gz",

      "_comment": "Compression type. E.g. `gzip`, `xz`, `bzip2`. See tar-out in guestfish(1) for all supported types.",
      "compression": "gzip",

      "_comment": "The Guestfish binary to use",
      "guestfish_binary": "guestfish",

      "_comment": "How long (in seconds) to wait for Guestfish to mount the file system",
      "guestfish_mount_timeout": 10,

      "_comment": "Keep the input artifact which was received by this post-processor",
      "keep_input_artifact": false
    }
  ]
}

Examples

See the Packer templates at DavidWittman/packer-openvz-templates.