Infrastructure as Code (IaC) is the practice of managing and provisioning infrastructure through code rather than manual processes. Instead of clicking through web consoles or running one-off commands, infrastructure is defined in version-controlled files that can be executed repeatedly to produce identical environments.
This approach treats infrastructure with the same rigor as application code: it's versioned, reviewed, tested, and deployed through automated pipelines.
## Why Infrastructure as Code?
### The problem with manual infrastructure
Traditional infrastructure management faces several challenges:
- **Inconsistency**: Manual steps vary between operators and environments
- **Undocumented**: Critical knowledge exists only in operators' heads
- **Error-Prone**: Human mistakes during repetitive tasks
- **Slow**: Manual provisioning takes hours or days
- **Untrackable**: No audit trail of what changed, when, or why
Infrastructure as Code addresses these challenges by making infrastructure:
**Declarative** - Describe the desired state, not the steps to achieve it. The IaC tool handles the implementation details.
**Versioned** - Every infrastructure change is committed to Git, providing complete history and the ability to rollback.
**Automated** - Infrastructure deploys through pipelines without human intervention, eliminating manual errors.
**Testable** - Infrastructure changes can be validated before production deployment.
**Documented** - The code itself is the documentation, always current and accurate.
**Reproducible** - The same code produces identical infrastructure every time, across all environments.
## Core Concepts
### Declarative vs imperative
**Imperative** approaches specify the exact steps: "Create a server, then install software, then configure networking."
**Declarative** approaches specify the desired outcome: "I need a server with this software and network configuration." The IaC tool determines the necessary steps.
Most modern IaC tools use the declarative approach, making them more maintainable and resilient.
### State Management
IaC tools maintain a "state" - a record of what infrastructure currently exists. When you change your code and re-run the tool, it compares the desired state (your code) with the actual state (what exists) and makes only the necessary changes.
This enables:
- **Drift detection** - Identify manual changes made outside IaC
- **Safe updates** - Modify only what changed
- **Dependency management** - Update resources in the correct order
### Idempotency
Running the same IaC code multiple times produces the same result. If infrastructure already matches the code, the tool makes no changes. This property is called idempotency and is essential for reliable automation.
## Infrastructure as Code in EDP
The Edge Developer Platform uses IaC extensively:
### Terraform and Terragrunt
[Terraform](terraform/) is our primary IaC tool for provisioning cloud resources. We use [Terragrunt](https://terragrunt.gruntwork.io/) as an orchestration layer to manage multiple Terraform modules and reduce code duplication.
Our implementation includes:
- **[infra-catalogue](https://edp.buildth.ing/DevFW/infra-catalogue)** - Reusable infrastructure components (modules, units, and stacks)
- **[infra-deploy](https://edp.buildth.ing/DevFW/infra-deploy)** - Full environment definitions using catalogue components
### Platform stacks
We organize infrastructure into [stacks](stacks/) - coherent bundles of related components:
Development, testing, and production environments are deployed from the same code. This eliminates the "works on my machine" problem at the infrastructure level.
Code review catches infrastructure errors before deployment. Automated testing validates changes. Version control enables instant rollback if problems occur.
Infrastructure configuration is explicit and discoverable in code. New team members can understand the platform by reading the repository rather than shadowing experienced operators.
Every infrastructure change is tracked in Git history with author, timestamp, and reason. This provides audit trails required for compliance and simplifies troubleshooting.
**State management complexity** - State files must be stored securely and accessed by multiple team members. State corruption can cause serious issues.
Our IaC tools ([infra-catalogue](https://edp.buildth.ing/DevFW/infra-catalogue) and [infra-deploy](https://edp.buildth.ing/DevFW/infra-deploy)) embody these principles and enable the platform's reliability.
