# Infrastructure as Code (IaC)

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

## Key Principles
- **Version Control**: All infrastructure configurations are stored in version control
- **Idempotency**: Running the same configuration produces the same result
- **Automation**: Infrastructure provisioning is automated and repeatable
- **Documentation**: Code serves as documentation

## Tools
- **Terraform**: Multi-cloud IaC tool using HCL
- **Ansible**: Configuration management and orchestration
- **CloudFormation**: AWS-native infrastructure provisioning
- **CloudFormation StackSets**: AWS-native cross-account/cross-region deployment extension for CloudFormation
- **Pulumi**: IaC using general-purpose programming languages
- **Terragrunt**: Wrapper for Terraform providing organization

## Best Practices
1. Use modules for reusable components
2. Separate state management (remote state with locking)
3. Implement proper access controls
4. Use workspaces for environment separation
5. Enable drift detection
6. Implement automated testing for IaC

## IaC Across DevOps Maturity Levels

| Maturity | IaC Maturity |
|----------|-------------|
| Phase 1 | Manual infrastructure management, servers managed individually, error-prone and slow |
| Phase 2 | Version control used for environments and configurations, but provisioning still manual |
| Phase 3 | Most infrastructure automated, provisioning repeatable and reliable |
| Phase 4 | Immutable infrastructure — old servers replaced rather than updated, managed through CI/CD pipelines |
| Phase 5 | Full automation, zero human intervention, infrastructure changes flow through automated pipelines |

## Sources
- [[sources/cloud-devop-maturity-guideline.md]]
- [[sources/devops-maturity-model-from-traditional-it-to-advanced-devops.md]]

## Related Concepts
- [[concepts/DevOps-Maturity]]
- [[concepts/CI-CD-Pipeline]]
- [[concepts/GitOps]]
- [[concepts/Scalability]]
- [[concepts/Cloud-Native]]

## Ingested
- Date: 2026-04-21
- Date: 2026-04-24 (updated with maturity level progression)