README.md

Terraform Modules Repository

Welcome to the Terraform Modules Repository. This repository contains a collection of reusable Terraform modules for AWS resources, making infrastructure provisioning efficient, consistent, and reliable.

Table of Contents

• Terraform Modules Repository
  • Table of Contents
  • Modules
  • Usage
    • Getting Started
  • Versioning
    • Best Practices for Versioning Terraform Modules:
  • Documentation Assets

Usage

Getting Started

To start using these Terraform modules, follow these steps:

1. Clone the Repository: Begin by cloning this repository to your local machine.
2. Start SSH Agent: Ensure your ssh agent is started and you have added your git private key. This is to allow you to downlonload the modules
   • Set up personal SSH keys on Linux
   • Set up personal SSH keys on Windows
3. Create the following files in a directory of your choice:

• main.tf: The main Terraform config
• variables.tf: For your terraform variables
• outputs.tf: For your Terraform Outputs
• versions.tf: For your Terraform provider and region setup

4. Follow the usage example specified in your required module. Examples are located in the README.md section of each module.
   • For example the ec2_autoscale module:

     module "tags" {
       source          = "[email protected]:UKHSA-Internal/devops-terraform-modules.git//terraform-modules/helpers/tags?ref=TF/helpers/tags/vALPHA_0.0.1"
     
       project         = "MyProject"
       client          = "ClientName"
       owner           = "OwnerName"
       environment     = "prod"
       additional_tags = {
         "CostCenter" = "IT-Dept"
       }
     }
     
     module "ec2_autoscale" {
       source                = "[email protected]:UKHSA-Internal/devops-terraform-modules.git//terraform-modules/ec2-autoscale?ref=ec2-autoscale/vALPHA_0.0.1"
     
       name                  = "MyProjectName"
       ami                   = "ami-0123456789abcdef0"
       instance_type         = "t2.micro"
       vpc_id                = "vpc-01234567"
       vpc_zone_identifiers  = ["subnet-0123456a", "subnet-0123456b"]
       
       # Example with SSH Access
       ingress_rules = [
         {
           from_port   = 22
           to_port     = 22
           protocol    = "tcp"
           cidr_blocks = ["0.0.0.0/0"]
         }
       ]
     
       tags                  = module.tags.tags
     }
     
     # Referencing outputs from the module
     output "asg_name" {
       value = module.ec2_autoscale.autoscaling_group_name
     }

   • Take note of the TF/helpers/tags/vALPHA_0.0.1. This is the version of the module you would like to use. We recommend you use the latest version of a module.

Templates

• WIP - To be Updated Soon!

Modules

• Modules are split up in the format <IaC_Tool>-modules/<cloud_provider>/<module_name>
  • All Terraform modules are located in the terraform-modules folder.
• Each Module has a README.md that is a autogenerated doc providing details of its respective module
• Each Module has a CHANGELOG.md that highlights changes made to the module

Versioning

• Modules in this repository are versioned using git tags in the format <environment>/<IaC_tool>/<cloud_provider>/<module_name>/v<sem_version>. For a list of all versions, check the tags in this repository.

Best Practices for Versioning Terraform Modules:

1. Semantic Versioning: Use SemVer (major.minor.patch) for clear version increments.
2. Document Changes: Update documentation and changelogs with each release.
3. Pin Versions: In configurations, specify module versions for consistency.
4. Limit Major Changes: Introduce backward-incompatible changes sparingly.
5. Testing: Test modules thoroughly before releasing, especially for major updates.

Documentation Assets

Additional documentation, diagrams, and assets related to the modules can be found in the doc folder.