terraform-azure

What this skill does

# Terraform Azure

Provision and manage Azure infrastructure with Terraform using the AzureRM provider. Covers provider configuration, remote state, resource groups, VNets, AKS, Key Vault, complete .tf file examples, and production workflows.

## When to Use

- You need multi-cloud or cloud-agnostic Infrastructure as Code.
- Your team standardizes on Terraform across AWS, Azure, and GCP.
- You need plan/apply workflows with change preview before deployment.
- You want modular, reusable infrastructure components.
- You need state locking and drift detection for production infrastructure.

## Prerequisites

```bash
# Install Terraform
wget -O- https://apt.releases.hashicorp.com/gpg | sudo gpg --dearmor -o /usr/share/keyrings/hashicorp-archive-keyring.gpg
echo "deb [signed-by=/usr/share/keyrings/hashicorp-archive-keyring.gpg] https://apt.releases.hashicorp.com $(lsb_release -cs) main" | sudo tee /etc/apt/sources.list.d/hashicorp.list
sudo apt update && sudo apt install terraform

# Verify installation
terraform version

# Install Azure CLI and login
curl -sL https://aka.ms/InstallAzureCLIDeb | sudo bash
az login
az account set --subscription "my-subscription-id"

# Create storage account for remote state
az group create --name tfstate-rg --location eastus
az storage account create \
  --name tfstate$(openssl rand -hex 4) \
  --resource-group tfstate-rg \
  --sku Standard_LRS \
  --encryption-services blob
az storage container create \
  --name tfstate \
  --account-name tfstateXXXXXXXX
```

## Provider Configuration

### providers.tf

```hcl
terraform {
  required_version = ">= 1.5.0"

  required_providers {
    azurerm = {
      source  = "hashicorp/azurerm"
      version = "~> 3.80"
    }
    azuread = {
      source  = "hashicorp/azuread"
      version = "~> 2.47"
    }
    random = {
      source  = "hashicorp/random"
      version = "~> 3.6"
    }
  }

  backend "azurerm" {
    resource_group_name  = "tfstate-rg"
    storage_account_name = "tfstate12345abc"
    container_name       = "tfstate"
    key                  = "prod.terraform.tfstate"
  }
}

provider "azurerm" {
  features {
    key_vault {
      purge_soft_delete_on_destroy    = false
      recover_soft_deleted_key_vaults = true
    }
    resource_group {
      prevent_deletion_if_contains_resources = true
    }
  }
  # Optional: use a specific subscription
  # subscription_id = var.subscription_id
}

provider "azuread" {}
```

### variables.tf

```hcl
variable "environment" {
  description = "Environment name (dev, staging, prod)"
  type        = string
  validation {
    condition     = contains(["dev", "staging", "prod"], var.environment)
    error_message = "Environment must be dev, staging, or prod."
  }
}

variable "location" {
  description = "Azure region for all resources"
  type        = string
  default     = "eastus"
}

variable "project_name" {
  description = "Project name used in resource naming"
  type        = string
  default     = "myapp"
}

variable "tags" {
  description = "Tags applied to all resources"
  type        = map(string)
  default     = {}
}

variable "sql_admin_password" {
  description = "SQL Server admin password"
  type        = string
  sensitive   = true
}

variable "aks_admin_group_id" {
  description = "Azure AD group ID for AKS admin access"
  type        = string
}

locals {
  name_prefix = "${var.project_name}-${var.environment}"
  common_tags = merge(var.tags, {
    environment = var.environment
    project     = var.project_name
    managed_by  = "terraform"
  })
}
```

### terraform.tfvars (per environment)

```hcl
# terraform.prod.tfvars
environment        = "prod"
location           = "eastus"
project_name       = "myapp"
aks_admin_group_id = "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"

tags = {
  cost_center = "engineering"
  owner       = "platform-team"
}
```

## Resource Group

### resource-group.tf

```hcl
resource "azurerm_resource_group" "main" {
  name     = "${local.name_prefix}-rg"
  location = var.location
  tags     = local.common_tags
}
```

## Virtual Network

### network.tf

```hcl
resource "azurerm_virtual_network" "main" {
  name                = "${local.name_prefix}-vnet"
  location            = azurerm_resource_group.main.location
  resource_group_name = azurerm_resource_group.main.name
  address_space       = ["10.0.0.0/16"]
  tags                = local.common_tags
}

resource "azurerm_subnet" "aks" {
  name                 = "aks-subnet"
  resource_group_name  = azurerm_resource_group.main.name
  virtual_network_name = azurerm_virtual_network.main.name
  address_prefixes     = ["10.0.1.0/22"]
}

resource "azurerm_subnet" "app" {
  name                 = "app-subnet"
  resource_group_name  = azurerm_resource_group.main.name
  virtual_network_name = azurerm_virtual_network.main.name
  address_prefixes     = ["10.0.8.0/24"]
}

resource "azurerm_subnet" "data" {
  name                 = "data-subnet"
  resource_group_name  = azurerm_resource_group.main.name
  virtual_network_name = azurerm_virtual_network.main.name
  address_prefixes     = ["10.0.9.0/24"]

  private_endpoint_network_policies_enabled = true
}

resource "azurerm_network_security_group" "app" {
  name                = "${local.name_prefix}-app-nsg"
  location            = azurerm_resource_group.main.location
  resource_group_name = azurerm_resource_group.main.name

  security_rule {
    name                       = "AllowHTTPS"
    priority                   = 100
    direction                  = "Inbound"
    access                     = "Allow"
    protocol                   = "Tcp"
    source_port_range          = "*"
    destination_port_range     = "443"
    source_address_prefix      = "*"
    destination_address_prefix = "*"
  }

  tags = local.common_tags
}

resource "azurerm_subnet_network_security_group_association" "app" {
  subnet_id                 = azurerm_subnet.app.id
  network_security_group_id = azurerm_network_security_group.app.id
}
```

## AKS Cluster

### aks.tf

```hcl
resource "azurerm_log_analytics_workspace" "aks" {
  name                = "${local.name_prefix}-law"
  location            = azurerm_resource_group.main.location
  resource_group_name = azurerm_resource_group.main.name
  sku                 = "PerGB2018"
  retention_in_days   = 30
  tags                = local.common_tags
}

resource "azurerm_kubernetes_cluster" "main" {
  name                = "${local.name_prefix}-aks"
  location            = azurerm_resource_group.main.location
  resource_group_name = azurerm_resource_group.main.name
  dns_prefix          = "${var.project_name}-${var.environment}"
  kubernetes_version  = "1.28"

  default_node_pool {
    name                = "system"
    vm_size             = "Standard_D4s_v5"
    enable_auto_scaling = true
    min_count           = 2
    max_count           = 5
    zones               = [1, 2, 3]
    vnet_subnet_id      = azurerm_subnet.aks.id
    os_disk_size_gb     = 128
    os_disk_type        = "Managed"
    max_pods            = 50

    node_labels = {
      role = "system"
    }
  }

  identity {
    type = "SystemAssigned"
  }

  network_profile {
    network_plugin    = "azure"
    network_policy    = "calico"
    service_cidr      = "10.1.0.0/16"
    dns_service_ip    = "10.1.0.10"
    load_balancer_sku = "standard"
  }

  azure_active_directory_role_based_access_control {
    managed                = true
    azure_rbac_enabled     = true
    admin_group_object_ids = [var.aks_admin_group_id]
  }

  oms_agent {
    log_analytics_workspace_id = azurerm_log_analytics_workspace.aks.id
  }

  key_vault_secrets_provider {
    secret_rotation_enabled  = true
    secret_rotation_interval = "2m"
  }

  tags = local.common_tags
}

resource "azurerm_kubernetes_cluster_node_pool" "app" {
  name                  = "app"
  kubernetes_cluster_id = azurerm_kubernetes_cluster.main.id
  vm_size               = "Standard_D8s_v5"
  enable_auto_scaling   = true
  min_count             = 2
  max_count             = 20
  zones