ops-infra-code

Infrastructure as Code (Terraform / OpenTofu)

Complete guide for Terraform and OpenTofu covering modules, tests, CI/CD and production patterns. Based on terraform-best-practices.com and Anton Babenko's enterprise experience.

When to use this Skill

Activate this skill to:

• Create Terraform/OpenTofu configurations or modules
• Set up the test infrastructure for IaC
• Choose between testing approaches (validate, plan, frameworks)
• Structure multi-environment deployments
• Implement CI/CD for infrastructure-as-code
• Review or refactor existing Terraform/OpenTofu projects

Do not use for:

• Basic syntax questions (Claude already knows)
• Provider-specific API reference (use the documentation)
• Cloud questions unrelated to Terraform/OpenTofu

Core Principles

1. Module Hierarchy

Type	When to use	Scope
Resource Module	Logical group of connected resources	VPC + subnets, Security group + rules
Infrastructure Module	Collection of resource modules	Several modules in a region/account
Composition	Complete infrastructure	Spans multiple regions/accounts

Hierarchy: Resource -> Resource Module -> Infrastructure Module -> Composition

2. Directory Structure

environments/        # Configurations per environment
├── prod/
├── staging/
└── dev/

modules/            # Reusable modules
├── networking/
├── compute/
└── data/

examples/           # Usage examples (also serve as tests)
├── complete/
└── minimal/

3. Naming Conventions

Resources:

# Good: Descriptive and contextual
resource "aws_instance" "web_server" { }
resource "aws_s3_bucket" "application_logs" { }

# Good: "this" for singleton resources (only one of this type)
resource "aws_vpc" "this" { }
resource "aws_security_group" "this" { }

# Avoid: Generic names for non-singletons
resource "aws_instance" "main" { }

Variables:

# Prefix with context
var.vpc_cidr_block          # Not just "cidr"
var.database_instance_class # Not just "instance_class"