Infrastructure as Code (IaC) — Explained with Examples

Infrastructure as Code (IaC) is the practice of managing and provisioning computing infrastructure — servers, networks, databases — through declarative or procedural configuration files rather than manual setup or interactive tools.

Instead of SSH-ing into a server to install packages or clicking through a cloud console, you write code that defines the desired state of your infrastructure. This code is version-controlled, reviewed, tested, and applied automatically. Two major approaches exist: declarative (you specify what you want, the tool figures out how — Terraform, CloudFormation) and procedural (you specify how step-by-step — Ansible, Chef).

Real-world analogy. IaC is like a recipe for a dish. Instead of calling a chef each time and describing the steps verbally, you write a cookbook. Anyone (or any machine) can follow the exact same recipe and produce the same meal every time.

Example (Terraform):

resource "aws_instance" "web" {
  ami           = "ami-0c55b159cbfafe1f0"
  instance_type = "t2.micro"

  tags = {
    Name = "WebServer"
  }
}

Related terms: CI/CD, Configuration Management, Immutable Infrastructure, GitOps, Containerization

Related tutorial: Terraform Basics