Learn the fundamentals of Terraform and Infrastructure as Code, including providers, resources, variables, state, modules, and the Terraform workflow.
Terraform Workflow
Write Configuration
Initialize Providers
Validate Configuration
Create Execution Plan
Apply Changes
Manage Infrastructure
Introduction
Terraform is an Infrastructure as Code tool that allows you to define, change, and manage cloud and on-premises infrastructure using human-readable configuration files.
Instead of manually creating infrastructure through cloud dashboards, you define the desired infrastructure in code. Terraform then compares that configuration with the managed infrastructure and determines the required changes.
Terraform follows a declarative approach, meaning you describe the desired end state while Terraform determines the operations required to create or modify the infrastructure.
Core Concepts
Before creating infrastructure with Terraform, it is important to understand the main building blocks used in Terraform configurations and workflows.
Infrastructure as Code allows you to define and manage infrastructure using configuration files instead of manually creating resources through dashboards.
Key Topics
Terraform providers connect Terraform to cloud platforms, infrastructure services, and other APIs so Terraform can manage their resources.
Key Topics
Resources represent infrastructure objects that Terraform can create, update, and manage through a provider.
Key Topics
Terraform tracks managed infrastructure using state information, which helps Terraform determine the changes required to reach the desired configuration.
Key Topics
Project Structure
Terraform configurations can be organized into multiple files. The Terraform CLI loads configuration files from the working directory and evaluates them together.
Usually contains the primary infrastructure resources and provider configuration for a Terraform project.
Defines input variables that allow Terraform configurations to be reused with different values.
Defines output values that Terraform displays after applying infrastructure changes.
Can define Terraform version requirements, required providers, backend configuration, and other Terraform settings.
Can provide values for input variables used by the Terraform configuration.
A directory that can contain reusable Terraform configuration components.
Your First Configuration
Terraform configurations use blocks and arguments to describe the infrastructure you want to manage. Providers connect Terraform to infrastructure APIs, while resource blocks define the objects to manage.
The example below demonstrates a simple provider and resource configuration structure.
Example main.tf
terraform {
required_providers {
aws = {
source = "hashicorp/aws"
}
}
}
provider "aws" {
region = "us-east-1"
}
resource "aws_instance" "web" {
ami = "ami-example"
instance_type = "t2.micro"
tags = {
Name = "terraform-web-server"
}
}Example variables.tf
variable "region" {
description = "AWS region"
type = string
default = "us-east-1"
}
variable "instance_type" {
description = "EC2 instance type"
type = string
default = "t2.micro"
}Input Variables
Variables allow you to parameterize Terraform configurations. Instead of hardcoding values for every environment, you can define reusable input variables.
This approach makes it easier to use the same Terraform configuration across development, testing, and production environments.
Output Values
Output values allow Terraform configurations to expose information about resources after Terraform applies the configuration.
Outputs can be useful for displaying resource IDs, addresses, endpoints, and other information generated during infrastructure provisioning.
Example outputs.tf
output "instance_id" {
description = "ID of the created instance"
value = aws_instance.web.id
}Terraform Workflow
Terraform follows a repeatable workflow for defining, reviewing, applying, and managing infrastructure changes.
Create Terraform configuration files that describe the infrastructure you want to manage.
Run terraform init to prepare the working directory and install required providers and modules.
Run terraform plan to review the proposed infrastructure changes before applying them.
Run terraform apply to execute the approved changes and provision or update infrastructure.
Update configuration files as infrastructure requirements change and repeat the Terraform workflow.
When infrastructure is no longer required, Terraform can remove managed resources using terraform destroy.
Terraform Commands
The Terraform CLI provides commands for initializing projects, formatting configuration, validating syntax, reviewing changes, applying infrastructure, and removing managed resources.
Always review planned infrastructure changes before applying them, especially when working with existing or production resources.
Basic Terraform Commands
# Initialize Terraform terraform init # Format configuration terraform fmt # Validate configuration terraform validate # Review planned changes terraform plan # Apply infrastructure changes terraform apply # Remove managed infrastructure terraform destroy
Use Cases
Provision and manage cloud resources such as virtual machines, networks, storage, and databases.
Manage infrastructure across different cloud providers using Terraform configurations and providers.
Manage Kubernetes-related infrastructure and resources using Infrastructure as Code workflows.
Create reusable Terraform modules for common infrastructure patterns and environments.
Integrate Terraform workflows into automated pipelines for consistent infrastructure changes.
Use configuration, variables, and reusable components to manage different infrastructure environments.
Learning Roadmap
Start with the basics of Infrastructure as Code and gradually move toward reusable configurations, state management, modules, cloud infrastructure, and automated Terraform workflows.
Learn why infrastructure can be defined using version-controlled configuration instead of manual resource creation.
Install the Terraform CLI and verify that the command is available in your terminal environment.
Understand blocks, arguments, expressions, resources, variables, and outputs in Terraform configuration files.
Connect Terraform to a cloud platform or infrastructure service using the appropriate provider.
Write Terraform resources and use the plan and apply workflow to manage infrastructure.
Continue with state management, modules, remote backends, reusable configurations, and automation workflows.
Best Practices
Store Terraform configuration in a version control system so infrastructure changes can be tracked and reviewed.
Format Terraform configuration consistently to improve readability and maintain a standard project structure.
Use validation tools and review your configuration before applying infrastructure changes.
Inspect the proposed execution plan before applying changes to understand what Terraform intends to modify.
Treat Terraform state carefully because it is important for tracking managed infrastructure and may contain sensitive information.
As projects grow, organize repeated infrastructure patterns into reusable and configurable modules.
Continue Learning
Explore Terraform concepts, Infrastructure as Code, providers, resources, state, modules, and automation.
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Next Step
Practice writing Terraform configurations, defining resources, using variables and outputs, reviewing execution plans, and managing infrastructure through Infrastructure as Code.