main.tf

# Assignment 2 - Vahid Konicanin
#
# Terraform code to deploy an Azure infrastructure with a virtual network, subnet, network security group,
# and two virtual machines (Windows and Linux), each with its own public IP address.

terraform {
  required_providers {
    azurerm = {
      source  = "hashicorp/azurerm"
      version = "=3.0.0"
    }
  }
}

provider "azurerm" {
  features {}
}

variable "prefix" {
  description = "Resource prefix"
  default     = "demo"
}

variable "location" {
  description = "Azure region"
  default     = "East US"
}

variable "admin_username" {
  description = "VM admin username"
  default     = "adminuser"
}

variable "admin_password" {
  description = "VM admin password"
  sensitive   = true
}

# VM configurations
locals {
  vms = {
    "win" = {
      os_type = "windows"
      size    = "Standard_D2s_v3"
      image   = {
        publisher = "MicrosoftWindowsServer"
        offer     = "WindowsServer"
        sku       = "2022-Datacenter"
        version   = "latest"
      }
    },
    "linux" = {
      os_type = "linux"
      size    = "Standard_B1s"
      image   = {
        publisher = "Canonical"
        offer     = "UbuntuServer"
        sku       = "18.04-LTS"
        version   = "latest"
      }
    }
  }
  
  # Common tags
  tags = {
    environment = "development"
    project     = "azure-demo"
  }
}

# Resource Group
resource "azurerm_resource_group" "main" {
  name     = "${var.prefix}-rg"
  location = var.location
  tags     = local.tags
}

# Network resources
resource "azurerm_virtual_network" "main" {
  name                = "${var.prefix}-vnet"
  address_space       = ["10.0.0.0/16"]
  location            = azurerm_resource_group.main.location
  resource_group_name = azurerm_resource_group.main.name
  tags                = local.tags
}

resource "azurerm_subnet" "main" {
  name                 = "${var.prefix}-subnet"
  resource_group_name  = azurerm_resource_group.main.name
  virtual_network_name = azurerm_virtual_network.main.name
  address_prefixes     = ["10.0.1.0/24"]
}

# Network Security Group with common rules
resource "azurerm_network_security_group" "main" {
  name                = "${var.prefix}-nsg"
  location            = azurerm_resource_group.main.location
  resource_group_name = azurerm_resource_group.main.name
  tags                = local.tags

  # SSH access
  security_rule {
    name                       = "SSH"
    priority                   = 1001
    direction                  = "Inbound"
    access                     = "Allow"
    protocol                   = "Tcp"
    source_port_range          = "*"
    destination_port_range     = "22"
    source_address_prefix      = "*"
    destination_address_prefix = "*"
  }

  # RDP access
  security_rule {
    name                       = "RDP"
    priority                   = 1002
    direction                  = "Inbound"
    access                     = "Allow"
    protocol                   = "Tcp"
    source_port_range          = "*"
    destination_port_range     = "3389"
    source_address_prefix      = "*"
    destination_address_prefix = "*"
  }
}

# Virtual machines and their dependencies
resource "azurerm_public_ip" "vm" {
  for_each            = local.vms
  name                = "${var.prefix}-${each.key}-ip"
  location            = azurerm_resource_group.main.location
  resource_group_name = azurerm_resource_group.main.name
  allocation_method   = "Dynamic"
  tags                = local.tags
}

resource "azurerm_network_interface" "vm" {
  for_each            = local.vms
  name                = "${var.prefix}-${each.key}-nic"
  location            = azurerm_resource_group.main.location
  resource_group_name = azurerm_resource_group.main.name
  tags                = local.tags

  ip_configuration {
    name                          = "internal"
    subnet_id                     = azurerm_subnet.main.id
    private_ip_address_allocation = "Dynamic"
    public_ip_address_id          = azurerm_public_ip.vm[each.key].id
  }
}

# Associate NSG with NICs
resource "azurerm_network_interface_security_group_association" "vm" {
  for_each                  = local.vms
  network_interface_id      = azurerm_network_interface.vm[each.key].id
  network_security_group_id = azurerm_network_security_group.main.id
}

# Create VMs using for_each
resource "azurerm_virtual_machine" "vm" {
  for_each              = local.vms
  name                  = "${var.prefix}-${each.key}"
  location              = azurerm_resource_group.main.location
  resource_group_name   = azurerm_resource_group.main.name
  network_interface_ids = [azurerm_network_interface.vm[each.key].id]
  vm_size               = each.value.size
  tags                  = local.tags

  delete_os_disk_on_termination    = true
  delete_data_disks_on_termination = true

  storage_image_reference {
    publisher = each.value.image.publisher
    offer     = each.value.image.offer
    sku       = each.value.image.sku
    version   = each.value.image.version
  }

  storage_os_disk {
    name              = "${var.prefix}-${each.key}-osdisk"
    caching           = "ReadWrite"
    create_option     = "FromImage"
    managed_disk_type = "Standard_LRS"
  }

  os_profile {
    computer_name  = "${each.key}vm"
    admin_username = var.admin_username
    admin_password = var.admin_password
  }

  dynamic "os_profile_linux_config" {
    for_each = each.value.os_type == "linux" ? [1] : []
    content {
      disable_password_authentication = false
    }
  }

  dynamic "os_profile_windows_config" {
    for_each = each.value.os_type == "windows" ? [1] : []
    content {
      provision_vm_agent = true
    }
  }
}

# Essential outputs
output "vm_public_ips" {
  value = {
    for name, ip in azurerm_public_ip.vm : name => ip.ip_address
  }
  description = "Public IP addresses of the VMs"
}

output "resource_group_name" {
  value = azurerm_resource_group.main.name
}