Setting Up the Second Group of Resources Security Groups Key Pairs

In this step, we’ll deploy AWS Security Groups and Key Pairs across multiple environments using community-maintained Terraform modules and Terragrunt.

Overview

Security Groups and Key Pairs are fundamental for protecting your AWS infrastructure and managing SSH access. By leveraging well-tested community modules, you can apply best practices without reinventing the wheel.

Prerequisites

Terraform v1.0+ installed
Terragrunt v0.35+ installed
AWS CLI configured with proper credentials
Existing VPC and networking resources deployed

Community Terraform Modules

Module	Description	Registry Link
terraform-aws-modules/security-group/aws	Creates customizable Security Groups	https://registry.terraform.io/modules/terraform-aws-modules/security-group/aws/latest
terraform-aws-modules/key-pair/aws	Manages EC2 Key Pairs and public keys	https://registry.terraform.io/modules/terraform-aws-modules/key-pair/aws/latest

Directory Structure

├── live
│   ├── development
│   │   └── security-groups
│   │       └── terragrunt.hcl
│   └── production
│       └── security-groups
│           └── terragrunt.hcl

Each environment (development and production) contains its own terragrunt.hcl to customize inputs and lifecycle settings.

terragrunt.hcl Example

include {
  path = find_in_parent_folders()
}

terraform {
  source = "git::ssh://[email protected]/your-org/terraform-aws-security-groups.git//modules/security-group?ref=v1.0.0"
}

inputs = {
  vpc_id                  = local.vpc_id
  environment             = "development"
  allowed_ssh_cidr_blocks = ["10.0.0.0/16"]
  ingress_rules = [
    { from_port = 22, to_port = 22, protocol = "tcp", cidr_blocks = ["10.0.0.0/16"] },
    { from_port = 80, to_port = 80, protocol = "tcp", cidr_blocks = ["0.0.0.0/0"] },
  ]
}

Deployment Steps

Change into the environment folder:
```
cd live/development/security-groups
```
Initialize Terragrunt (which also initializes Terraform):
```
terragrunt init
```
Review the execution plan:
```
terragrunt plan
```
Apply changes to provision resources:
```
terragrunt apply
```

Note

Repeat these steps in each environment directory (development, production) to maintain isolation and environment-specific configurations.

Customizing Input Variables

Adjust the following inputs for each environment:

Variable	Description	Example
`allowed_ssh_cidr_blocks`	CIDR blocks permitted for SSH access	`["203.0.113.0/24"]`
`ingress_rules`	List of ingress rules for the Security Group	See `terragrunt.hcl Example` above
`key_pair_name`	Name for the EC2 Key Pair	`"dev-keypair"`
`public_key_path`	Local path to your public SSH key	`"~/.ssh/id_rsa.pub"`

Warning

Never commit your private SSH keys (~/.ssh/id_rsa) to version control. Always reference only the public key in Terraform.

Links and References

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