Infrastructure as Code Pattern

IaC Overview

Infrastructure as Code (IaC) is a key capability identified in DORA research that enables high-performing organizations to manage their infrastructure using version-controlled declarative configurations.

Core Principles

Principle	Description	Implementation
Declarative	Define desired state, not steps	Terraform, ARM templates
Version Control	Track all infrastructure changes	Git
Immutable	Replace rather than modify	Containers, VM images
Idempotent	Same input yields same result	Terraform state

Implementation Guide

1. Infrastructure Definition

# Example Terraform Configuration
terraform {
  required_providers {
    azurerm = {
      source  = "hashicorp/azurerm"
      version = "~> 3.0"
    }
  }
}

resource "azurerm_kubernetes_cluster" "main" {
  name                = "fawkes-aks"
  location            = "eastus"
  resource_group_name = azurerm_resource_group.main.name
  dns_prefix          = "fawkes"

  default_node_pool {
    name       = "default"
    node_count = 3
    vm_size    = "Standard_D2_v2"
  }

  identity {
    type = "SystemAssigned"
  }
}

2. GitOps Integration

# ArgoCD Application for Infrastructure
apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: fawkes-infrastructure
spec:
  source:
    repoURL: https://github.com/paruff/fawkes.git
    path: infrastructure/terraform
    targetRevision: HEAD
  destination:
    server: https://kubernetes.default.svc
    namespace: infrastructure

Best Practices

1. Code Organization

infrastructure/
├── environments/
│   ├── production/
│   │   └── main.tf
│   └── staging/
│       └── main.tf
├── modules/
│   ├── kubernetes/
│   │   └── main.tf
│   └── networking/
│       └── main.tf
└── shared/
    └── variables.tf

2. Security Controls

# Example Security Policy
resource "azurerm_key_vault" "main" {
  name                = "fawkes-vault"
  location            = azurerm_resource_group.main.location
  resource_group_name = azurerm_resource_group.main.name
  tenant_id          = data.azurerm_client_config.current.tenant_id

  sku_name = "standard"

  network_acls {
    default_action = "Deny"
    bypass         = "AzureServices"
  }
}

Key Metrics

Based on DORA research, track these infrastructure metrics:

Metric	Elite Performance	Implementation
Infrastructure Change Success Rate	> 95%	`success_rate = successful_changes / total_changes`
Infrastructure Recovery Time	< 1 hour	`recovery_time = restore_time - failure_time`
Infrastructure Deployment Time	< 30 minutes	`deployment_time = end_time - start_time`

Testing Strategy

1. Unit Testing

# Example Terraform Test
provider "test" {}

resource "test_assertions" "network" {
  component = "network"

  equal "cidr_block" {
    description = "CIDR block should match expected value"
    got         = module.network.cidr_block
    want        = "10.0.0.0/16"
  }
}

2. Integration Testing

#!/bin/bash
# Infrastructure Integration Test
terraform init
terraform plan -out=tfplan
terraform apply tfplan

# Validate resources
az aks show --name fawkes-aks --resource-group fawkes-rg

Common Anti-Patterns

❌ Avoid These Practices: - Manual infrastructure changes - Untested infrastructure code - Sharing state files - Hard-coded credentials

✅ Instead Do This: - Automate all changes - Implement comprehensive testing - Use remote state storage - Use secrets management

Tools Integration

Category	Tools	Purpose
IaC	Terraform, Pulumi	Infrastructure definition
Version Control	Git	Configuration management
CI/CD	Azure DevOps, GitHub Actions	Automation
Testing	Terratest, Inspec	Validation
Security	Checkov, tfsec	Security scanning

References

View Examples Implementation Guide