How Terraform Works — Full Flow

Write Code (.tf files)
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        v
terraform init       <-- Downloads provider plugins, sets up backend
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        v
terraform validate   <-- Checks syntax errors
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terraform plan       <-- Compares current state vs desired state, shows diff
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terraform apply      <-- Applies the changes to real infrastructure
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        v
State File Updated   <-- terraform.tfstate updated with new real state
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terraform destroy    <-- Destroys all managed resources (when needed)

Terraform Core Files

project/
├── main.tf           # Main resources
├── variables.tf      # Input variable declarations
├── outputs.tf        # Output value declarations
├── provider.tf       # Provider configuration
├── terraform.tfvars  # Actual variable values
├── backend.tf        # Remote state backend config
└── .terraform/       # Local plugins/cache (auto-generated by init)

Section 1 — Core Concepts (Must Know)

Q1. What is Terraform and why is it used?

Terraform is an open-source Infrastructure as Code (IaC) tool by HashiCorp. It lets you define cloud infrastructure (servers, databases, networks) in .tf files and manage them through code.

Why use Terraform:

• Consistent, repeatable infrastructure
• Version control your infra like code
• Works across multiple cloud providers (AWS, Azure, GCP)
• Tracks state to understand what already exists
• Automates create, update, delete operations

Q2. What is Infrastructure as Code (IaC)?

IaC means managing and provisioning infrastructure through code/config files instead of manually clicking in a cloud console.

Benefits:

• Reproducible environments