What are Terraform Modules?

Think of Terraform modules as pre-built LEGO sets. They're reusable blocks of infrastructure code that you can plug and play into your main Terraform configuration. This helps you:

• Organize your code: Break down complex infrastructure into smaller, manageable parts.

• Reuse code: Avoid writing the same code multiple times, saving time and reducing errors.

• Share code: Share modules with others or publish them to public registries.

Creating a Module

1. Create a new directory: This will be the root of your module for example ec2 directory.

2. Create a main.tf file: This is where you'll define the resources and variables that make up your module.

3. Define variables (optional): Use variable blocks to accept input values from your main configuration.

4. Define resources: Use resource blocks to define the infrastructure components you want to create.

Example Module (Creating an EC2 instance):

Terraform

main.tf

variable "ami" 
{    type        = string    
description = "AMI ID of the EC2 instance"  
}  
variable "instance_type" 
{    
    type        = string    
    description = "Instance type of the EC2 instance"     
}  
resource "aws_instance" "example" {    ami           = var.ami    
instance_type = var.instance_type  
}  

Using a Module in Your Main Configuration

1. Add the module to your main configuration: Use the module block to reference your module.

2. Provide input values: Pass the required values for your module's variables.

Example Main Configuration:

module "ec2_instance" 
{    
  source = "./modules/ec2"    
  ami           = "ami-0c55b159cbfafe1f0"    instance_type = "t2.micro"  
}  

Benefits of Using Modules

• Modularity: Break down complex infrastructure into smaller, manageable parts.

• Reusability: Avoid writing the same code multiple times, saving time and reducing errors.

• Shareability: Share modules with others or publish them to public registries.

• Version Control: Track changes to modules and manage different versions.

• Maintainability: Easier to update and manage modules compared to modifying a large main configuration.

By using Terraform modules, you can create more organized, efficient, and reusable infrastructure code.