TFLAB01-Your First Terraform Configuration from Scratch

Your First Terraform Configuration from Scratch

🔧 Terraform Core ⭐ Beginner terraform block required_version required_providers provider resource init / plan / apply / destroy

Scenario

You have just installed Terraform on your machine and want to understand the absolute basics: how to tell Terraform which version to use, how to declare a cloud provider, how to define a resource, and how to run the core workflow — init, plan, apply, and destroy.

To keep things dead simple, you will create a single S3 bucket. The goal is not to learn S3 — it's to learn how Terraform files are structured and how the workflow executes.

Your Objectives
  • Create a terraform {} block that pins the Terraform CLI version to >= 1.5.0 and declares the hashicorp/aws provider with version ~> 5.0.
  • Configure the aws provider for the us-east-1 region.
  • Create a single aws_s3_bucket resource with a unique bucket name and a ManagedBy = "terraform" tag.
  • Run terraform init to download the provider plugin.
  • Run terraform plan to preview the changes.
  • Run terraform apply to create the bucket.
  • Run terraform destroy to clean up.

Additional Context

The terraform {} block is the configuration's identity card. It tells anyone reading the code (and Terraform itself) what version of the CLI is expected and which provider plugins are required. Without required_providers, Terraform will still try to guess the provider from the resource type prefix, but being explicit avoids surprises — especially when providers share resource naming patterns.

The ~> 5.0 version constraint is called the pessimistic constraint operator. It means "any version >= 5.0 and < 6.0". This lets you get patch and minor updates automatically while preventing a major version upgrade that could contain breaking changes.

versions.tf

# versions.tf
# This block pins the Terraform CLI and provider versions.
# Always include this — reproducibility starts here.

terraform {
  required_version = ">= 1.5.0"

  required_providers {
    aws = {
      source  = "hashicorp/aws"   # Full address: registry.terraform.io/hashicorp/aws
      version = "~> 5.0"          # Allow 5.x updates, block 6.0+
    }
  }
}

main.tf

# main.tf

# Configure the AWS provider — tells Terraform which region to target.
provider "aws" {
  region = "us-east-1"
}

# Create a single S3 bucket.
# S3 bucket names must be globally unique across ALL AWS accounts.
resource "aws_s3_bucket" "my_first_bucket" {
  bucket = "my-first-tf-bucket-demo-2024"

  tags = {
    Name      = "my-first-bucket"
    ManagedBy = "terraform"
  }
}

Workflow Commands

# Step 1: Initialise — downloads the AWS provider plugin into .terraform/
terraform init

# Step 2: Preview — shows what Terraform WILL do (no changes made yet)
terraform plan

# Step 3: Apply — creates the resources (type "yes" to confirm)
terraform apply

# Step 4: Verify — confirm the bucket exists
aws s3 ls | grep my-first-tf-bucket

# Step 5: Destroy — removes everything Terraform created
terraform destroy
✓ Expected Output After Apply
Apply complete! Resources: 1 added, 0 changed, 0 destroyed.

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