Terraform Architecture

Terraform is an open-source infrastructure as code (IaC) tool developed by HashiCorp. It allows users to define and provision infrastructure using a declarative configuration language.

The architecture of Terraform involves several key components and concepts:

1. Configuration Files:

   • Terraform uses configuration files written in HashiCorp Configuration Language (HCL) to describe the desired infrastructure. These files typically have a .tf extension.
   • Configuration files specify the resources, providers, and other settings needed to create and manage infrastructure.

2. Providers:

   • Providers are plugins in Terraform that define and interact with a particular infrastructure platform or service, such as AWS, Azure, Google Cloud, or others.
   • Each provider has its own set of resources and data sources that can be managed using Terraform.

3. Resources:

   • Resources are the fundamental building blocks in Terraform configurations. They represent infrastructure components like virtual machines, networks, databases, etc.
   • Resource declarations specify the desired state of the infrastructure, and Terraform manages the creation, updating, and deletion of these resources to achieve that state.

4. State Files:

   • Terraform maintains a state file that keeps track of the current state of the infrastructure being managed. This file is used to plan and apply changes, as well as to track the relationships between resources.
   • The state file can be stored locally or remotely, and it helps Terraform understand what changes need to be made to reach the desired state.

5. Execution Plan:

   • When you run terraform plan, Terraform generates an execution plan based on the configuration files and the current state. The plan outlines what actions Terraform will take to bring the infrastructure to the desired state.

6. Execution Apply:

   • Running terraform apply applies the changes specified in the execution plan. Terraform will create, update, or delete resources as needed to match the desired state.

7. Backends:

   • Terraform supports various backends for storing the state file. Common backends include local, remote, and version-controlled options like AWS S3, Azure Storage, and others.
   • Choosing an appropriate backend is important for collaboration, versioning, and maintaining the state file securely.

8. Modules:

   • Modules in Terraform allow you to organize and reuse configuration code. They encapsulate a set of resources and can be used as building blocks for creating larger and more complex infrastructures.

9. Variables and Outputs:

   • Variables are used to parameterize configurations, making them more flexible and reusable. Outputs allow you to expose certain values from the configuration for reference or use in other Terraform configurations.

Understanding these key components and concepts is crucial for effectively using Terraform to manage infrastructure as code. The tool provides a scalable and consistent approach to provisioning and managing infrastructure across various cloud and on-premises environments.