Last Updated on April 16, 2024 by Arnav Sharma
Terraform, a product by HashiCorp, has revolutionized the concept of “Infrastructure as Code” (IaC). At the heart of Terraform lies the concept of a “module.” A Terraform module is a reusable set of Terraform code that abstracts a piece of infrastructure. Instead of writing repetitive Terraform configurations for similar infrastructure setups, users can create a module once and reuse it across different projects. The root module is the entry point, and from there, one can use child modules to further configure and deploy specific AWS resources like EC2 instances and security groups. These modules can be stored in a Git repository, such as GitHub, allowing for version control and collaboration. With input variables, you can customize the module for different environments, and the module output can be used to pass information to another module or the root module. By adhering to best practices, storing modules in the Terraform Registry, and ensuring proper syntax and security measures, Terraform modules can greatly simplify and streamline your infrastructure deployment process.
In every Terraform project, the power of modularity is evident. A Terraform module is a set of Terraform configuration files bundled together, allowing developers to create reusable infrastructure with ease. Think of it as a building block in your infrastructure code. While you can write single Terraform configurations for specific tasks, using modules in Terraform lets you group these configurations, making them more manageable and scalable. There are various sources from which modules can be utilized. You can use local modules stored in your module directory or remote modules from the Terraform Cloud. For those who prefer a broader community-driven approach, modules from the Terraform Registry, both public and private, offer a plethora of pre-written infrastructure solutions. These published modules adhere to module best practices and come with code examples, simplifying the process of developing modules. If you’re using Terraform Enterprise, the integration is even smoother. The parent module can refer to this child module using the same syntax, and Terraform will automatically handle the intricacies. Whether you’re using the AWS provider or any other, Terraform keeps track of the state and relationships, ensuring that your complex infrastructure remains consistent. For those new to this open-source infrastructure as code tool, creating your first module might seem daunting, but with resources like Terraform’s configuration language and the vast community writing Terraform modules, the journey becomes much more navigable.
Terraform Modules
Let’s say we have three applications (1, 2 and 3) with three different environments as shown below:
Now, each application have its own resource requirements and will need a lot of Terraform coding.
Hence we use Terraform Modules.
What we can do is create a Modules Directory with four required resources and then consume the same
set of code for all the three apps and three different environments:
This is how it will look:
Instead of writing code for VM for each app or having inconsistencies in the IaC deployments, we use modules.
FAQ – Terraform Modules
Q: What is the output in the context of Terraform?
A: The output refers to the output variable in Terraform, which displays results or data from your Terraform configuration.
Q: What are the best practices when working with Terraform?
A: Best practices include using the Terraform module registry, ensuring every Terraform configuration is modular and reusable, and understanding module basics for efficient infrastructure management.
Q: How do you use Terraform for infrastructure management?
A: To use Terraform, you need to create a Terraform configuration file, define your infrastructure with Terraform modules, and then run Terraform commands to deploy the defined infrastructure.
Q: What does “infrastructure as code” (IaC) mean?
A: Infrastructure as code (IaC) refers to the use of Terraform and similar tools to manage and provision infrastructure using a programming language-like syntax.
Q: How do you access the module output in Terraform?
A: You can access the module output using the module block in your Terraform configuration, which will display the results from the module code.
Q: Are there any module best practices in Terraform?
A: Yes, module best practices include developing reusable modules, understanding module inputs and outputs, and storing modules in a module folder or directory for organization.
Q: How does Terraform integrate with AWS?
A: Terraform integrates with cloud providers like AWS using provider-specific modules. These modules allow you to manage AWS resources and services using Terraform.
Q: What is a child module in Terraform?
A: A child module in Terraform is a module called by another module. This allows for modular and hierarchical infrastructure definitions.
Q: How do you maintain the state of your infrastructure in Terraform?
A: The state of the infrastructure is maintained in the Terraform state file, which keeps track of the resources Terraform manages.
Q: What are IaC best practices in Terraform?
A: IaC best practices in Terraform include using custom modules from the public Terraform registry, ensuring configurations are modular, and version-controlling your Terraform code using git or other version control systems.
Q: How do you use Terraform modules effectively?
A: To use Terraform modules effectively, understand the module basics, utilize module inputs and outputs, and refer to this module documentation for complex configurations.
Q: What should you consider when creating your first Terraform project?
A: When creating your first Terraform project, consider the infrastructure you want to manage, define module sources, and ensure you have a clear directory structure for your Terraform configuration file and associated modules.
keywords: programming language terraform supports module can also private module