📍 Introduction:

module.tf is a Terraform configuration file that is used to define reusable modules. A module is a self-contained piece of infrastructure that can be used as a building block for larger infrastructures. Modules can contain multiple resources and configurations, and can be parameterized to accept input variables.

🔹 module.tf Example:

Here's an example module.tf file that defines a module for creating an AWS EC2 instance:

provider "aws" {
  region = var.region
}

resource "aws_instance" "example" {
  ami           = var.ami
  instance_type = var.instance_type
  tags = var.tags
}

This module creates an EC2 instance with the specified AMI, instance type, and tags. The provider block configures the AWS provider to use the specified region.

To use this module in another configuration, you would create a main.tf file that references the module, like this:

module "ec2_instance" {
  source = "./ec2_instance"

  region         = "us-west-2"
  ami            = "ami-0c55b159cbfafe1f0"
  instance_type  = "t2.micro"
  tags = {
    Name = "example-instance"
  }
}

In this example, the module block references the module defined in the ./ec2_instance directory. The input variables region, ami, instance_type, and tags are passed to the module.

🔹 Subtopics:

Other subtopics related to module.tf include:

⚜ Module outputs:

In addition to input variables, modules can also define output values that can be used in other configurations. Output values are defined in the module using the output block, and can be referenced in the calling configuration using the module.<module_name>.<output_name> syntax.

⚜ Module sources:

Modules can be sourced from various locations, including local directories, Git repositories, and the Terraform Registry.

⚜ Module composition:

Modules can be composed of other modules, allowing for modular architectures that can be easily scaled and reused.

⚜ Module versioning:

Modules can be versioned using tags or commit hashes, allowing for reproducible builds and consistent infrastructure across environments.

⚜ Module testing:

Modules can be tested using automated testing frameworks, allowing for increased confidence in the functionality and correctness of the infrastructure.

⚜ Module organization:

To facilitate module reuse and maintainability, it is recommended to organize modules into a directory structure that reflects the desired hierarchy of the infrastructure. For example, modules related to networking could be stored in a networking directory, while modules related to databases could be stored in a databases directory.

📍 Conclusion:

In Terraform, module.tf is used to define reusable modules that can be used as building blocks for larger infrastructures. A module is a self-contained piece of infrastructure that can contain multiple resources and configurations, and can be parameterized to accept input variables. This allows for modular architectures that can be easily scaled and reused across multiple projects. module.tf files define the resources and configurations within a module, while the main.tf file references the module and passes in the necessary input variables. Modules can also define output values that can be used in other configurations, and can be composed of other modules for even greater flexibility. By using modules in Terraform, infrastructure can be built and managed more efficiently, with greater consistency and reproducibility.