Kitchen-Terraform

Kitchen-Terraform enables verification of Terraform state.

Kitchen-Terraform provides a set of Test Kitchen plugins which enable a system to use Test Kitchen to converge a Terraform configuration and verify the resulting Terraform state with InSpec controls.

As Kitchen-Terraform integrates several distinctive technologies in a nontrivial manner, reviewing the documenation of each of the aforementioned products is strongly encouraged.

Installation

Terraform

Kitchen-Terraform integrates with the Terraform command-line interface to implement a Test Kitchen workflow for Terraform modules.

Installation instructions can be found in the Terraform: Install Terraform article.

Kitchen-Terraform supports versions of Terraform in the interval of >= 0.10.2, < 0.12.0.

tfenv can be used to manage versions of Terraform on the system.

Ruby

Kitchen-Terraform is written in Ruby which requires an interpreter to be installed on the system.

Installation instructions can be found in the Ruby: Installing Ruby article.

Kitchen-Terraform aims to support all versions of Ruby that are in "normal" or "security" maintenance, which is currently the interval of >= 2.2, < 2.5.

rbenv can be used to manage versions of Ruby on the system.

Kitchen-Terraform Ruby Gem

Each version of Kitchen-Terraform is published as a Ruby gem to RubyGems.org which makes them readily available for installation on a system.

RubyGems

To install a version of Kitchen-Terraform using the default Ruby package manager, RubyGems, run a command like the following example.

Installing Kitchen-Terraform with RubyGems

gem install kitchen-terraform --version 3.0.0

More information can be found in the RubyGems: Installing Gems article.

Bundler

Bundler can also be used to manage versions of Kitchen-Terraform on the system in a manner that is easily reproducible on other systems.

First, create a Gemfile with contents like the following example. The pessimistic pinning of the version is recommended to benefit from the semantic versioning of the Ruby gem.

Defining Kitchen-Terraform as a dependency for Bundler

source "https://rubygems.org/" do
  gem(
    "kitchen-terraform",
    "~> 3.0"
  )
end

Second, run the following command.

Installing Kitchen-Terraform with Bundler

bundle install

More information can be found in the Bundler: In Depth article.

Usage

Configuration

Kitchen-Terraform provides three Test Kitchen plugins which must be configured in a Test Kitchen configuration file in order to successfully test Terraform configuration.

The Terraform driver manages the state of the Terraform root module.

The Terraform provisioner uses the Terraform driver to apply changes to the Terraform state.

The Terraform verifier uses InSpec to verify the Terraform state.

More information can be found in the Ruby gem documentation.

Example

Assume there is a system which has Kitchen-Terraform and Docker installed.

Assume the working directory on said system a hierarchy like the following examples.

Directory hierarchy

.
├── .kitchen.yml
├── main.tf
└── test
    └── integration
        └── example
            ├── controls
            │   ├── operating_system.rb
            └── inspec.yml

./.kitchen.yml

driver:
  name: terraform

provisioner:
  name: terraform

transport:
  name: ssh
  password: root

verifier:
  name: terraform
  groups:
    - name: container
      port: 2222
      username: root

platforms:
  - name: ubuntu

suites:
  - name: example

./main.tf

provider "docker" {
  host    = "unix://localhost/var/run/docker.sock"
}

data "docker_registry_image" "ubuntu" {
  name = "rastasheep/ubuntu-sshd:latest"
}

resource "docker_image" "ubuntu" {
  name          = "${data.docker_registry_image.ubuntu.name}"
  pull_triggers = ["${data.docker_registry_image.ubuntu.sha256_digest}"]
}

resource "docker_container" "ubuntu" {
  image    = "${docker_image.ubuntu.name}"
  must_run = true
  name     = "ubuntu_container"

  ports {
    external = 2222
    internal = 22
  }
}

./test/integration/example/inspec.yml

name: example

./test/integration/example/controls/operating_system.rb

# frozen_string_literal: true

control "operating_system" do
  describe "the operating system" do
    subject do
      command("lsb_release -a").stdout
    end

    it "is Ubuntu" do
      is_expected.to match /Ubuntu/
    end
  end
end

Running the following command would initialize the working directory for Terraform, create a Docker container by applying the configuration file, and verify that the container is running Ubuntu.

Verifying with Kitchen-Terraform

$ kitchen test
-----> Starting Kitchen...
...
$$$$$$ Running command `terraform init...`
...
$$$$$$ Running command `terraform apply...`
...
       docker_container.ubuntu: Creation complete after 1s...

       Apply complete! Resources: 2 added, 0 changed, 0 destroyed.
...
       Finished converging <example-ubuntu>...
...
-----> Verifying <example-ubuntu>...
       Verifying host 'localhost' of group 'container'
...
  ✔  operating_system: the operating system is Ubuntu
...
Profile Summary: 1 successful control, 0 control failures, 0 controls skipped
...