Week 7 - Day 1: IaC Introduction

📚 Learning Objectives

Understand what Infrastructure as Code is
Learn the benefits of IaC over manual provisioning
Introduction to Terraform and its ecosystem
Install and configure Terraform

📖 Core Concepts (2 Hours)

What is Infrastructure as Code?

Infrastructure as Code (IaC) is the practice of managing and provisioning infrastructure through machine-readable configuration files rather than manual processes.

Declarative: Define what you want, not how to create it
Version Controlled: Track changes like application code
Reproducible: Same config = same infrastructure
Automated: No manual clicking in consoles

Manual vs IaC Approach

Manual Process:
┌─────────────────────────────────────┐
│ 1. Login to AWS Console            │
│ 2. Click EC2 → Launch Instance     │
│ 3. Select AMI, instance type       │
│ 4. Configure security groups       │
│ 5. Add storage, tags               │
│ 6. Launch and wait...              │
│ [Time: 10-15 min, Error-prone]     │
└─────────────────────────────────────┘

IaC Process (Terraform):
┌─────────────────────────────────────┐
│ 1. Write configuration file        │
│ 2. Run: terraform apply            │
│ 3. Done!                           │
│ [Time: 2 min, Reproducible]        │
└─────────────────────────────────────┘

Benefits of IaC

✓ Consistency    - Same environment every time
✓ Speed          - Deploy infrastructure in minutes
✓ Documentation  - Config files document your infra
✓ Version Control- Git history of all changes
✓ Reusability    - Use modules for common patterns
✓ Cost Control   - Easy to destroy and recreate
✓ Collaboration  - Team reviews infrastructure changes

IaC Tools Comparison

Tool            Language        Cloud Support
─────────────────────────────────────────────
Terraform       HCL             Multi-cloud
CloudFormation  YAML/JSON       AWS only
Pulumi          Python/JS/etc   Multi-cloud
Ansible         YAML            Multi-cloud
ARM Templates   JSON            Azure only

Why Terraform?
• Cloud agnostic (AWS, Azure, GCP, etc.)
• Large community and modules
• Declarative and readable syntax
• State management built-in

Terraform Architecture

┌──────────────────────────────────────────┐
│           Terraform Core                  │
│  (Parses config, builds resource graph)   │
└─────────────────┬────────────────────────┘
                  │
    ┌─────────────┼─────────────┐
    ▼             ▼             ▼
┌───────┐    ┌───────┐    ┌───────┐
│  AWS  │    │ Azure │    │  GCP  │
│Provider│   │Provider│   │Provider│
└───┬───┘    └───┬───┘    └───┬───┘
    │            │            │
    ▼            ▼            ▼
  AWS API    Azure API    GCP API

🔬 Hands-on Lab (2.5 Hours)

Lab 1: Install Terraform

# On Ubuntu/Debian
wget -O- https://apt.releases.hashicorp.com/gpg | sudo gpg --dearmor -o /usr/share/keyrings/hashicorp-archive-keyring.gpg
echo "deb [signed-by=/usr/share/keyrings/hashicorp-archive-keyring.gpg] https://apt.releases.hashicorp.com $(lsb_release -cs) main" | sudo tee /etc/apt/sources.list.d/hashicorp.list
sudo apt update && sudo apt install terraform

# On macOS
brew tap hashicorp/tap
brew install hashicorp/tap/terraform

# Verify installation
terraform version
terraform -help

Lab 2: Configure AWS Credentials

# Install AWS CLI if not installed
curl "https://awscli.amazonaws.com/awscli-exe-linux-x86_64.zip" -o "awscliv2.zip"
unzip awscliv2.zip
sudo ./aws/install

# Configure credentials
aws configure
# Enter:
# - AWS Access Key ID
# - AWS Secret Access Key
# - Default region (e.g., us-east-1)
# - Default output format (json)

# Verify configuration
aws sts get-caller-identity

Lab 3: First Terraform File

# Create project directory
mkdir -p ~/terraform-labs/lab1
cd ~/terraform-labs/lab1

# Create main.tf
cat > main.tf << 'EOF'
terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 5.0"
    }
  }
}

provider "aws" {
  region = "us-east-1"
}

# This just outputs a message - no resources created yet
output "hello" {
  value = "Hello from Terraform!"
}
EOF

# Initialize Terraform
terraform init

# See what Terraform will do
terraform plan

# Apply (creates nothing yet, just outputs)
terraform apply

✅ Day 1 Checklist

Understand what IaC is and its benefits
Know why Terraform is popular
Terraform installed and working
AWS CLI configured with credentials
Created first Terraform configuration