IAC

IaC, or Infrastructure as Code, is the practice of managing and provisioning infrastructure through machine-readable configuration files rather than manual hardware configuration or interactive provisioning. It enables automation, reproducibility, and versioning, allowing environments to be created consistently and rapidly.

There are declarative and imperative approaches. Declarative IaC expresses the desired end state (e.g., certain resources exist with specific properties); the tool determines the steps to reach that state. Imperative IaC specifies commands to run in order. Most modern tools blend these styles to achieve idempotence and reproducibility.

Common benefits include speed, consistency across environments, reduced human error, auditable changes, easier rollbacks, and better collaboration between development and operations. It also supports disaster recovery planning and cost management through reproducible environments.

Popular IaC tools include Terraform, which is cloud-agnostic and uses a declarative language; AWS CloudFormation for AWS; Ansible, Puppet, Chef and Salt for configuration management; and Pulumi, which allows general-purpose languages like TypeScript, Python, Go to define infrastructure. Tools may manage both provisioning and configuration.

Many tools maintain a state that records the current infrastructure, enabling idempotent changes. Drift can occur when resources are altered outside the IaC workflow, requiring reconciliation. Plans or previews show intended changes before application.

Best practices involve storing configuration in version control, using automated tests and policy checks, secret management, and separating responsibilities among teams. Security and compliance should be considered in design, with least privilege and continuous monitoring.

IaC is a core part of modern cloud-native and DevOps practices, enabling continuous delivery, scalable environments, and consistent deployments across development, testing, and production.