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Infrastructure as Code

What is IaC?

Infrastructure as Code (IaC) means provisioning and managing infrastructure using code, instead of manually creating resources via a cloud console (clicks, drag & drop).

In IaC:

  • Infrastructure is defined declaratively
  • The same code can create, update, or destroy resources
  • Infrastructure becomes repeatable and predictable

Traditional vs IaC

graph LR
A[Manual Cloud Console
Click / Drag / Drop] -->|Human Actions| B[Infrastructure]

C[Infrastructure Code
Terraform / ARM / CloudFormation] -->|Automated| D[Infrastructure]

Why Do We Use Infrastructure as Code?

"Why write code when we can just use the cloud console?"

Manual provisioning works fine for:

  • Personal projects
  • Learning or experiments

But it does not scale.

Example: Three-Tier Application

Assume provisioning infra for:

  • Load Balancer
  • Application Servers
  • Database

Time taken manually: ~2 hours

graph TD
LB[Load Balancer] --> APP[Application Servers]
APP --> DB[Database]

That’s acceptable for one environment.

Multiple Environments Problem

In a company, you usually have:

  • Dev
  • QA
  • Staging
  • Production

Manual provisioning time:

Environments Time
1 2 hrs
4 8 hrs 
graph LR
Dev --> QA --> Staging --> Prod

Now imagine:

  • Hundreds of servers
  • Multiple regions
  • Multiple teams

Manual setup becomes:

  • Slow
  • Error-prone
  • Hard to maintain

Real-World Challenges Without IaC

❌ Hard to decommission infra → High cloud cost
❌ Environments differ → "Works on my machine" issue
❌ No easy rollback
❌ No visibility into changes
❌ Security & compliance risks 

graph TD
Manual[Manual Infra] --> Errors[Human Errors]
Manual --> Cost[High Cost]
Manual --> Drift[Environment Drift]

Benefits of Infrastructure as Code

Key Advantages

  • Consistent environments across Dev / QA / Prod
  • Write once, deploy many (single codebase)
  • Faster provisioning
  • Reduced human error
  • Cost savings via automation
  • Version control (Git tracks infra changes)
  • Automated cleanup & scheduled destruction
  • Easy to create identical production-like environments
  • Developers can focus on application development
graph LR
Code[Infra Code] --> Repeatable[Repeatable Infra]
Code --> Secure[Secure & Auditable]
Code --> Fast[Fast Provisioning]
Code --> Cheap[Cost Optimized]