Understand the practice of managing infrastructure through code.
Infrastructure as Code (IaC) is a fundamental DevOps practice that involves managing and provisioning IT infrastructure using machine-readable definition files, rather than physical hardware configuration or interactive configuration tools. Essentially, it's the practice of treating your infrastructure—servers, load balancers, networks, databases—the same way you treat your application code. Your infrastructure specification is stored in version control (like Git), just like your application's source code. This brings numerous advantages. It enables 'Automation' at scale; you can deploy an entire complex environment with a single command. It promotes 'Consistency' by eliminating the manual errors and configuration drift that plague manually managed systems, ensuring that your development, staging, and production environments are identical. It provides 'Version Control' for your infrastructure, so you can track every change, understand the history of your environment, and easily roll back to a previous state if something goes wrong. Furthermore, it facilitates 'Collaboration' by allowing multiple team members to work on and review infrastructure code. There are two main approaches to IaC: declarative and imperative. A declarative approach (used by tools like Terraform and AWS CloudFormation) focuses on the 'what'—you define the desired end state, and the tool figures out how to get there. An imperative approach (used by tools like Ansible and traditional shell scripts) focuses on the 'how'—you write scripts that specify the exact commands to be run to achieve the desired state.