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Azure VM with CloudFlare DNS… by Terraform

By Tomica Kaniski in Other 25/08/2020 0 Comment

I like Terraform! 🙂

Had an idea the other day – I wanted to make myself an Ubuntu virtual machine on Microsoft Azure and also create a corresponding DNS record inside my kaniski.eu domain (currently hosted at CloudFlare… like, I guess, half of the Internet). Of course, I can do all that by using both of the portals, but this time I wanted to do it with Terraform, so it can be easily brought up and down, reusable, etc.

For this, you’ll need:

  • Microsoft Azure subscription
  • CloudFlare account (with a domain attached to its DNS servers, of course)
  • Terraform (v0.13)
  • (optional) Visual Studio Code
  • (or you can all do it inside Azure Cloud Shell)

To configure Terraform with your Azure subscription, you’ll need:

  • Azure Subscription ID
  • Tenant ID
  • Client ID
  • Client secret

There’s a nice document about setting it all up – https://docs.microsoft.com/en-us/azure/developer/terraform/overview.

For accessing CloudFlare API via Terraform, you’ll need the following info from your CloudFlare account page:

  • e-mail address
  • CloudFlare zone ID
  • CloudFlare account ID

  • CloudFlare API key

Be really careful with using your Azure/CloudFlare keys (can’t be stressed enough!)!

Also note that the following code is only one way of doing it, one that suits me for this purpose, not best practice or the prettiest code ever! 🙂

The whole example (main.tf) looks like this (it can/should be improved, but that’s not really the point here and now):

main.tf
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# providers
provider "azurerm" {
  version = "~> 2.24"
 
  subscription_id = var.subscription_id
  tenant_id       = var.tenant_id
  client_id       = var.client_id
  client_secret   = var.client_secret
 
  features {}
}
 
provider "cloudflare" {
  version = "~> 2.10.0"
 
  email      = var.cf_email
  api_key    = var.cf_apikey
  account_id = var.cf_accountid
}
 
# resource group
resource "azurerm_resource_group" "example-rg" {
  name     = "example-rg"
  location = "West Europe"
}
 
# network
resource "azurerm_virtual_network" "example-net" {
  name                = "example-net"
  location            = azurerm_resource_group.example-rg.location
  resource_group_name = azurerm_resource_group.example-rg.name
  address_space       = ["10.11.0.0/16"]
}
 
# subnet
resource "azurerm_subnet" "example-sub" {
  name                 = "example-sub"
  resource_group_name  = azurerm_resource_group.example-rg.name
  virtual_network_name = azurerm_virtual_network.example-net.name
  address_prefixes     = ["10.11.12.0/24"]
}
 
# nics
resource "azurerm_network_interface" "myvm-nic" {
  name                 = "myvm-nic"
  location             = azurerm_resource_group.example-rg.location
  resource_group_name  = azurerm_resource_group.example-rg.name
  enable_ip_forwarding = true
 
  ip_configuration {
    name                          = "myvm-nic-ip-config"
    subnet_id                     = azurerm_subnet.example-sub.id
    private_ip_address_allocation = "Static"
    private_ip_address            = "10.11.12.4"
    public_ip_address_id          = azurerm_public_ip.myvm-ip.id
  }
}
 
# public ips
resource "azurerm_public_ip" "myvm-ip" {
  name                = "myvm-ip"
  location            = azurerm_resource_group.example-rg.location
  resource_group_name = azurerm_resource_group.example-rg.name
  allocation_method   = "Static"
}
 
# network security group
resource "azurerm_network_security_group" "example-nsg" {
  name                = "example-nsg"
  location            = azurerm_resource_group.example-rg.location
  resource_group_name = azurerm_resource_group.example-rg.name
 
  security_rule {
    name                       = "SSH"
    priority                   = 100
    direction                  = "Inbound"
    access                     = "Allow"
    protocol                   = "Tcp"
    source_port_range          = "*"
    destination_port_range     = "22"
    source_address_prefix      = "*"
    destination_address_prefix = "10.11.12.4"
  }
}
 
resource "azurerm_subnet_network_security_group_association" "example-sub-nsg-assoc" {
  subnet_id                 = azurerm_subnet.example-sub.id
  network_security_group_id = azurerm_network_security_group.example-nsg.id
}
 
# vms
resource "azurerm_virtual_machine" "myvm" {
  name                          = "myvm"
  location                      = azurerm_resource_group.example-rg.location
  resource_group_name           = azurerm_resource_group.example-rg.name
  network_interface_ids         = [azurerm_network_interface.myvm-nic.id]
  vm_size                       = "Standard_DS1_v2"
  delete_os_disk_on_termination = true
 
  storage_image_reference {
    publisher = "Canonical"
    offer     = "UbuntuServer"
    sku       = "19_10-daily-gen2"
    version   = "latest"
  }
 
  storage_os_disk {
    name              = "myvm-osdisk"
    caching           = "ReadWrite"
    create_option     = "FromImage"
    managed_disk_type = "Standard_LRS"
  }
 
  os_profile {
    computer_name  = "myvm"
    admin_username = var.admin_username
  }
 
  os_profile_linux_config {
    disable_password_authentication = true
    ssh_keys {
      key_data = file("~/.ssh/id_rsa.pub")
      path     = "/home/${var.admin_username}/.ssh/authorized_keys"
    }
  }
}
 
# cloudflare dns
resource "cloudflare_record" "myvm-dns" {
  zone_id = var.cf_zoneid
  name    = "myvm"
  value   = azurerm_public_ip.myvm-ip.ip_address
  type    = "A"
}

Variables used in this simple example are (terraform.tfvars):

terraform.tfvars
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subscription_id = ""
tenant_id       = ""
client_id       = ""
client_secret   = ""
admin_username  = ""
cf_zoneid       = ""
cf_email        = ""
cf_apikey       = ""
cf_accountid    = ""

Just note one more thing – I’m using the current version of Terraform (v0.13) and version 2 of the CloudFlare provider (notable changes between the v1 and v2 are listed at https://registry.terraform.io/providers/cloudflare/cloudflare/latest/docs/guides/version-2-upgrade).

As always, running terraform init will take care of the missing providers and install them as needed. Also, running terraform plan can give us an estimation of what exactly will be done and terraform fmt will make our code look nice! 🙂

When I run this code (terraform apply), it completes successfully (of course) and provisions 9 items and, more important – gives me info about the DNS name and IP address of the provisioned VM (which I already know, but still):

Next is a series of checks:

  • DNS record really exists in CloudFlare DNS?

  • resources are really provisioned in Azure?

  • SSH into the VM works?

And that’s it – when you’re done, you can use terraform destroy and it’s all gone! 🙂

Cheers!

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