Terraform Fundamentals

Terraform is an infrastructure-as-code tool for provisioning and changing infrastructure through declarative configuration. You describe the desired result, and Terraform determines the changes required to reach it.

Practice as you read

👉 Launch the official Terraform Sandbox. It comes with Terraform, Docker, LocalStack, and the AWS CLI already set up, so you can try the examples without installing anything.

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The Learning Path

The pages below are arranged in the order that works best for a newcomer. Each stage builds on the one before it.

How to use this guide

• New to Terraform? Follow the numbers from 1 to 32 in order.
• Already know the basics? Jump straight to the part you need.
• Status: ✅ means the page is ready to read. 🚧 means it is planned and coming soon.

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The Building Blocks at a Glance

Every Terraform project is made from the same handful of pieces. This table is a quick map of what each one is for.

Building block	What it is	Example
Provider	A plugin that lets Terraform talk to a service such as AWS	provider "aws" { ... }
Resource	Something Terraform creates and manages	resource "aws_s3_bucket" "demo" { ... }
Data source	A read-only lookup of something that already exists	data "aws_vpc" "main" { ... }
Variable	An input value supplied from outside the code	var.region
Local	A named value calculated inside the code	local.bucket_name
Output	A value shown or shared after apply	output "bucket_name" { ... }
Module	A reusable folder of Terraform code	module "network" { ... }
State	Terraform's record of what it has already built	terraform.tfstate

The workflow in four commands

terraform init      # download the providers your code needs
terraform plan      # preview what will change
terraform apply     # build it for real
terraform destroy   # remove everything when you are done

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Part 1: Getting Started

Install Terraform, give it access to AWS, and run the four commands you will use every day.

#	Topic	What you will learn	Status
1	Installing Terraform	Install the Terraform CLI and check that it works	✅ Ready
2	Connecting Terraform to AWS	Give Terraform credentials and a region so it can create real resources	✅ Ready
3	Terraform Core Commands	The four commands you use every time: init, plan, apply, destroy	✅ Ready

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Part 2: Core Concepts

The ideas that every later page relies on.

#	Topic	What you will learn	Status
4	Terraform Safety Nets	Tags, prevent_destroy, replace vs update, and renaming safely	✅ Ready
5	Terraform Providers Explained	What providers are, how to pin versions, and how to use several at once	✅ Ready
6	HCL Syntax Basics	Blocks, arguments, types, and expressions	✅ Ready
7	Terraform State	What the state file is, local vs remote, locking, and drift	✅ Ready

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Part 3: Reusable and Readable Code

Stop hardcoding values and start organizing your project.

#	Topic	What you will learn	Status
8	Terraform Input Variables	Types, defaults, validation, and all the ways to set a value	✅ Ready
9	Terraform Outputs	Show and share values after apply	✅ Ready
10	Terraform Project Structure	Standard files, folders, and separating environments	✅ Ready
11	Terraform Locals	Name a value once and reuse it everywhere	✅ Ready
12	Terraform Data Sources	Read information about things that already exist	✅ Ready
13	Terraform Resource Dependencies	How Terraform decides the build order, and when to use depends_on	✅ Ready

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Part 4: Dynamic Code and Meta-Arguments

Create many resources from one block, and make choices inside your code.

#	Topic	What you will learn	Status
14	count	Create several copies of a resource	🚧 Coming soon
15	for_each	Create resources from a map or a set, each with its own settings	🚧 Coming soon
16	Conditional Expressions	Choose a value with condition ? a : b	🚧 Coming soon
17	Built-in Functions	Work with strings, lists, maps, and more	🚧 Coming soon
18	Lifecycle Meta-Arguments	Control how Terraform creates, replaces, and protects resources	🚧 Coming soon

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Part 5: Building AWS Infrastructure

Put the concepts to work on real AWS services.

#	Topic	What you will learn	Status
19	VPCs and Subnets	Build the network your resources live in	🚧 Coming soon
20	Security Groups	Control which traffic can reach your resources	🚧 Coming soon
21	EC2 Instances	Launch servers into your network	🚧 Coming soon
22	IAM	Roles, policies, and least-privilege access	🚧 Coming soon
23	SSM Parameters and Secrets	Keep configuration and secrets out of your code	🚧 Coming soon
24	DynamoDB	Create and manage NoSQL tables	🚧 Coming soon
25	Lambda and SQS	Run serverless functions and connect them with queues	🚧 Coming soon

Why networking comes before servers

An EC2 instance needs a subnet and a security group to launch into, so VPCs and Subnets (19) and Security Groups (20) come before EC2 Instances (21).

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Part 6: Modules

Package your configuration so it can be reused.

#	Topic	What you will learn	Status
26	Using Modules	Call existing modules and pass them values	🚧 Coming soon
27	Writing Modules	Build your own reusable modules with inputs and outputs	🚧 Coming soon

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Part 7: State and Team Workflows

Work safely as a team and as your state grows.

#	Topic	What you will learn	Status
28	Remote State on S3	Store state in a shared bucket with locking	🚧 Coming soon
29	Workspaces	Keep separate state for each environment from one codebase	🚧 Coming soon
30	Moving and Removing State	Rename or stop tracking resources without destroying them	🚧 Coming soon
31	Import and Replace	Bring existing resources under Terraform, and force a rebuild when needed	🚧 Coming soon

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Part 8: Quality and Troubleshooting

Keep your code clean and find problems early.

#	Topic	What you will learn	Status
32	fmt, validate, and Debugging Drift	Format and check your code, then find and fix differences between your code and reality	🚧 Coming soon

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More to Explore

Topics that pair well with everything above and may be added later:

• dynamic blocks for generating repeated nested settings
• terraform console for testing expressions interactively
• Security best practices for secrets and state
• Running Terraform in a CI/CD pipeline
• Writing automated tests with terraform test