Terraform Azure config - demo

main.tf

# Configure the Azure provider
terraform {
  required_providers {
    azurerm = {
      source  = "hashicorp/azurerm"
      version = "~> 3.0.2"
    }
  }

  required_version = ">= 1.1.0"
}

provider "azurerm" {
  features {}
}

resource "azurerm_resource_group" "rg" {
  name     = "myTFResourceGroup"
  location = "eastus2"
}

# Create a virtual network
resource "azurerm_virtual_network" "vnet" {
  name                = "vnet-lb-demo"
  resource_group_name = azurerm_resource_group.rg.name
  location            = azurerm_resource_group.rg.location
  address_space       = ["10.0.0.0/16"]
}

# Create a subnet for the VMs and NICs
resource "azurerm_subnet" "subnet" {
  name                 = "subnet-lb-demo"
  resource_group_name  = azurerm_resource_group.rg.name
  virtual_network_name = azurerm_virtual_network.vnet.name
  address_prefixes     = ["10.0.1.0/24"]
}

# Create a public IP for the load balancer
resource "azurerm_public_ip" "lb_pub_ip" {
  name                = "lb-public-ip"
  resource_group_name = azurerm_resource_group.rg.name
  location            = azurerm_resource_group.rg.location
  allocation_method   = "Static"
  sku                 = "Standard"
}
# Create the load balancer with a frontend configuration
resource "azurerm_lb" "lb" {
  name                = "myLoadBalancer"
  location            = azurerm_resource_group.rg.location
  resource_group_name = azurerm_resource_group.rg.name
  sku                 = "Standard"

  frontend_ip_configuration {
    name                 = "LoadBalancerFrontEnd"
    public_ip_address_id = azurerm_public_ip.lb_pub_ip.id
  }
}

# Create the backend address pool for the load balancer
resource "azurerm_lb_backend_address_pool" "backend_pool" {
  name                = "backendPool"
  loadbalancer_id     = azurerm_lb.lb.id
}

# Create VM1 (Linux)
resource "azurerm_linux_virtual_machine" "vm1" {
  name                = "vm1"
  resource_group_name = azurerm_resource_group.rg.name
  location            = azurerm_resource_group.rg.location
  size                = "Standard_DS1_v2"
  admin_username      = "azureuser"
  network_interface_ids = [
    azurerm_network_interface.nic1.id
  ]
  
  os_disk {
    caching              = "ReadWrite"
    storage_account_type = "Standard_LRS"
  }
  
  source_image_reference {
    publisher = "Canonical"
    offer     = "0001-com-ubuntu-server-jammy"
    sku       = "22_04-lts-gen2"
    version   = "22.04.202503240"
  }
  
  admin_ssh_key {
    username   = "azureuser"
    public_key = file("~/.ssh/id_rsa.pub")
  }
}

# Create VM2 (Linux)
resource "azurerm_linux_virtual_machine" "vm2" {
  name                = "vm2"
  resource_group_name = azurerm_resource_group.rg.name
  location            = azurerm_resource_group.rg.location
  size                = "Standard_DS1_v2"
  admin_username      = "azureuser"
  network_interface_ids = [
    azurerm_network_interface.nic2.id
  ]
  
  os_disk {
    caching              = "ReadWrite"
    storage_account_type = "Standard_LRS"
  }
  
  source_image_reference {
    publisher = "Canonical"
    offer     = "0001-com-ubuntu-server-jammy"
    sku       = "22_04-lts-gen2"
    version   = "22.04.202503240"
  }
  
  admin_ssh_key {
    username   = "azureuser"
    public_key = file("~/.ssh/id_rsa.pub")
  }
}

# Public IP for VM1
resource "azurerm_public_ip" "vm1_public_ip" {
  name                = "vm1-public-ip"
  resource_group_name = azurerm_resource_group.rg.name
  location            = azurerm_resource_group.rg.location
  allocation_method   = "Static"
  sku                 = "Standard"
}

# Public IP for VM2
resource "azurerm_public_ip" "vm2_public_ip" {
  name                = "vm2-public-ip"
  resource_group_name = azurerm_resource_group.rg.name
  location            = azurerm_resource_group.rg.location
  allocation_method   = "Static"
  sku                 = "Standard"
}

resource "azurerm_network_security_group" "nsg" {
  name                = "nsg-vms"
  resource_group_name = azurerm_resource_group.rg.name
  location            = azurerm_resource_group.rg.location

  # Allow SSH traffic on port 22
  security_rule {
    name                       = "Allow-SSH"
    priority                   = 100
    direction                  = "Inbound"
    access                     = "Allow"
    protocol                   = "Tcp"
    source_address_prefix      = "*"
    destination_address_prefix = "*"
    source_port_range          = "*"
    destination_port_range     = "22"
  }

  # Allow DNS queries on TCP port 53
  security_rule {
    name                       = "Allow-DNS-TCP"
    priority                   = 110
    direction                  = "Inbound"
    access                     = "Allow"
    protocol                   = "Tcp"
    source_address_prefix      = "*"
    destination_address_prefix = "*"
    source_port_range          = "*"
    destination_port_range     = "53"
  }

  # Allow DNS queries on UDP port 53
  security_rule {
    name                       = "Allow-DNS-UDP"
    priority                   = 120
    direction                  = "Inbound"
    access                     = "Allow"
    protocol                   = "Udp"
    source_address_prefix      = "*"
    destination_address_prefix = "*"
    source_port_range          = "*"
    destination_port_range     = "53"
  }
}



# Create NIC for VM1 and associate it with the backend pool
resource "azurerm_network_interface" "nic1" {
  name                = "nic1"
  location            = azurerm_resource_group.rg.location
  resource_group_name = azurerm_resource_group.rg.name

  ip_configuration {
    name                          = "internal"
    subnet_id                     = azurerm_subnet.subnet.id
    private_ip_address_allocation = "Dynamic"
    public_ip_address_id          = azurerm_public_ip.vm1_public_ip.id
  }
}

resource "azurerm_network_interface_backend_address_pool_association" "nic1" {
  network_interface_id    = azurerm_network_interface.nic1.id
  ip_configuration_name   = "internal"
  backend_address_pool_id = azurerm_lb_backend_address_pool.backend_pool.id
}

resource "azurerm_network_interface_security_group_association" "nic1" {
  network_interface_id      = azurerm_network_interface.nic1.id
  network_security_group_id = azurerm_network_security_group.nsg.id
}


# Create NIC for VM2 and associate it with the backend pool
resource "azurerm_network_interface" "nic2" {
  name                = "nic2"
  location            = azurerm_resource_group.rg.location
  resource_group_name = azurerm_resource_group.rg.name
  

  ip_configuration {
    name                          = "internal"
    subnet_id                     = azurerm_subnet.subnet.id
    private_ip_address_allocation = "Dynamic"
  }
}

resource "azurerm_network_interface_backend_address_pool_association" "nic2" {
  network_interface_id    = azurerm_network_interface.nic2.id
  ip_configuration_name   = "internal"
  backend_address_pool_id = azurerm_lb_backend_address_pool.backend_pool.id
}
resource "azurerm_network_interface_security_group_association" "nic2" {
  network_interface_id      = azurerm_network_interface.nic2.id
  network_security_group_id = azurerm_network_security_group.nsg.id
}


# Load balancing rule for TCP port 53
resource "azurerm_lb_rule" "lb_rule_tcp_53" {
  name                           = "lbrule-tcp-53"
  loadbalancer_id                = azurerm_lb.lb.id
  protocol                       = "Tcp"
  frontend_port                  = 53
  backend_port                   = 53
  frontend_ip_configuration_name = "LoadBalancerFrontEnd"
  backend_address_pool_ids        = [azurerm_lb_backend_address_pool.backend_pool.id]
  idle_timeout_in_minutes        = 4
}

# Load balancing rule for UDP port 53
resource "azurerm_lb_rule" "lb_rule_udp_53" {
  name                           = "lbrule-udp-53"
  loadbalancer_id                = azurerm_lb.lb.id
  protocol                       = "Udp"
  frontend_port                  = 53
  backend_port                   = 53
  frontend_ip_configuration_name = "LoadBalancerFrontEnd"
  backend_address_pool_ids        = [azurerm_lb_backend_address_pool.backend_pool.id]
  idle_timeout_in_minutes        = 4
}