AWS AMI image builder module

Terraform module which creates Amazon Machine Images on AWS with the help of packer

Prerequisites

This module uses a few tools that need to be installed locally

• python
  • module semver
• packer
• jq

Features

This module integrates packer with terraform by running packer a part of a local provisioner script.

The packer config format (json) does not support commenting, complex interpolation etc., so that maintaining, updating and versioning packer builds can be a challenge. This module converts its own image configuration format (terraform variables) to packer templates.

Currently only the AMI Builder (EBS backed) is supported.

The config format used by this module is a list of image groups. Each image group uses the same set of provisioners
(https://www.packer.io/docs/provisioners/index.html) to configure the images defined within that group, while currently only file and shell provisioners are supported. Each image config uses the same parameters as the EBS builder, while credentials and AMI permissions are handled automatically and wont have to be set for each individual image.

While the list of image groups is a flat list, a hierarchy of dependent images is maintained using the source_ami_name parameter on each image config. With the help of this parameter, a DAG is created, from which only branches with no interdependency will result in an image build. In other words: If an image A depends on image B, and image B needs to be upgraded, image A will not be considered to be built unless the dependent image reached its desired version.

Usage

module "images" {
  source = "janschumann/terraform-aws-images"

  default_allowed_accounts = [
    "1234567890",
    "0123456789"
  ]

  images              = [{
    name = "base"
    provisioners = [{
        type = "shell"
        scripts = [
          "./scripts/base.sh",
        ]
    }],
    images = [{
        name            = "my-aws-linux"
        description     = "my aws linux base image"
        source_ami_name = "aws-linux"
        source_ami_user = "ec2-user"
    }]
  }]
}

Requirements

Name	Version
terraform	>= 0.12
aws	~> 2.7
external	~> 1.0
local	~> 1.0

Inputs

Name	Description	Type	Default	Required
builder_credentials	The credentials to use to build the AMI	map(string)	{}	no
debug	Only create packer build files	bool	false	no
default_allowed_accounts	A list of account ids to allow images access to by default	list(string)	[]	no
default_builder_config	The default builder config.	map(any)	{}	no
image_versions_path	Path to a json file that contains the image versions as a map of strings.	string	"./versions.json"	no
images	A list of maps describing the images to build	any	n/a	yes
jq_executeable	Path to the jq executable	string	"/usr/bin/env jq"	no
packer_executeable	Path to the packer executable	string	"/usr/bin/env packer"	no
python_executeable	Path to the python executable to execute the packerize script with. Make sure to install all requirements in requirements.txt	string	"/usr/bin/env python"	no
source_images	A list of source images. By default the latest aws-linux image is referenced	list(object({ name = string, description = string, owner = string, search_pattern = string }))	[ { "description": "aws linux 2", "name": "aws-linux", "owner": "137112412989", "search_pattern": "amzn2-ami-hvm-*-x86_64-ebs" } ]	no

Outputs

Name	Description
latest	The list of the latest versions of the resulting amis
source_images	The list of current source amis

Authors

Module managed by Jan Schumann.

License

Apache 2 Licensed. See LICENSE for full details.