Terragrunt DRY deploy tutorial across multiple environments with CloudTruth run

This repository contains Terragrunt HCL that will create an AWS Instance in us-west-2 and an S3 bucket deployed with Terragrunt utilizing CloudTruth to manage Terraform variable keys and values for a development, production, and staging environment.

Rather than using hardcoded and scattered Terragrunt inputs to define environment parameter values, we will inject inputs directly from a CloudTruth project.

Terragrunt folder structure

# terragrunt-cloudtruth-deploy
├── development
│   ├── instance
│   │   └── terragrunt.hcl
│   ├── s3
│   │   └── terragrunt.hcl
│   └── terragrunt.hcl
│       
├── production
│   ├── instance
│   │   └── terragrunt.hcl
│   ├── s3
│   │   └── terragrunt.hcl
│   └── terragrunt.hcl
│       
└── staging
    ├── instance
    │   └── terragrunt.hcl
    ├── s3
    │   └── terragrunt.hcl
    └── terragrunt.hcl
        

The instance and s3 sub-folders contain a terragrunt.hcl file that set the source parameter to point at the specific modules in the terragrunt-cloudtruth-modules repo. They also include the top level terragrunt.hcl file in the development, production, and staging folders.

The top level terragrunt.hcl file for each environment specifies the aws provider configuration.

1. Clone this repo terragrunt-cloudtruth-deploy

2. Create a CloudTruth Project with the CloudTruth CLI

   Create a CloudTruth Project

   cloudtruth project set Terragrunt
   
   

   Setup CloudTruth Parameters required by the Terraform Modules

   cloudtruth --project Terragrunt parameter set TF_VAR_ami -v ami-830c94e3
   cloudtruth --project Terragrunt parameter set TF_VAR_instance_type -v t2.micro
   cloudtruth --project Terragrunt parameter set TF_VAR_availability_zone_names -v \[\"us-west-2a\",\ \"us-west-2b\"\]
   cloudtruth --project Terragrunt parameter set TF_VAR_resource_tags -v \{\"Name\":\"Cloudtruth-Instance\",\"project\":\"CloudTruth\ Run\ Terraform\",\"environment\":\"default\"\}
   
   

   Create CloudTruth Environments

   cloudtruth environment set development
   cloudtruth environment set production
   cloudtruth environment set staging
   
   

   Override variable TF_VAR_resource_tags in each environment

   cloudtruth --project Terragrunt --env development parameter set TF_VAR_resource_tags -v \{\"Name\":\"CloudTruth-development\",\"project\":\"CloudTruth\ Run\ Terraform\",\"environment\":\"development\"\}
   cloudtruth --project Terragrunt --env production parameter set TF_VAR_resource_tags -v \{\"Name\":\"CloudTruth-production\",\"project\":\"CloudTruth\ Run\ Terraform\",\"environment\":\"production\"\}
   cloudtruth --project Terragrunt --env staging parameter set TF_VAR_resource_tags -v \{\"Name\":\"CloudTruth-staging\",\"project\":\"CloudTruth\ Run\ Terraform\",\"environment\":\"staging\"\}
   
   

   Verify your project parameters

   You can verify the parameters we will be using for Terragrunt. In this case we will list parameters for the environment development, note that the TF_VAR_resource_tags has a source of development and the tags reference the development environment.

   cloudtruth --project Terragrunt --env development parameters ls -v

   +--------------------------------+----------------------------------------------------------------------------------------------------+-------------+--------+--------+-------------+
   | Name                           | Value                                                                                              | Source      | Type   | Secret | Description |
   +--------------------------------+----------------------------------------------------------------------------------------------------+-------------+--------+--------+-------------+
   | TF_VAR_ami                     | ami-830c94e3                                                                                              | default     | static | false   |             |
   | TF_VAR_availability_zone_names | ["us-west-2a", "us-west-2b"]                                                                       | default     | static | false  |             |
   | TF_VAR_instance_type           | t2.micro                                                                                           | default     | static | false  |             |
   | TF_VAR_resource_tags           | {"Name":"CloudTruth-development","project":"CloudTruth Run Terraform","environment":"development"} | development | static | false  |             |
   +--------------------------------+----------------------------------------------------------------------------------------------------+-------------+--------+--------+-------------+
   

Terragrunt will respect any TF_VAR_xxx variables you’ve manually set in your environment. Using CloudTruth Run we will pass the configured TF_VAR_xxx variables directly to the Terraform modules with Terragrunt. This allows you to keep your configuration DRY and have a centrally managed source of truth for your configuration management.

Change directory to terragrunt-cloudtruth-deploy/development/

From terragrunt-cloudtruth-deploy/development/ execute the following command which passes variables from the CloudTruth project Terragrunt for the development environment into terragrunt:

cloudtruth --project Terragrunt --env development run -- terragrunt run-all apply

You have now created an instance in EC2 and an S3 bucket with Terragrunt and CloudTruth!

You can view the outputs that display the parameter values from the CloudTruth Development environment. terragrunt run-all output

AMI = <sensitive>
instance_name = "CloudTruth-development"
instance_type = "t2.micro"
zone = "us-west-2a"
s3_bucket_name = "cloudtruth-grunt-free-panda"
s3_tag_name = "CloudTruth-development"

You can change to the production or staging directories and pass the respective CloudTruth environment to deploy various settings across your different infrastructure!

Destroy the AWS resources:

cloudtruth --project Terragrunt --env development run -- terragrunt run-all destroy