Overriding default values from terraform public registry modules - terraform

Question

Using below terraform code. main.tf file is as below
data "azurerm_resource_group" "tf-rg-external" {
name = var.rg_name
}
data "azurerm_virtual_network" "tf-vn" {
name = var.vnet_name
resource_group_name = var.rg_name
}
# Reference existing subnet
data "azurerm_subnet" "tf-sn" {
name = var.subnet_name
virtual_network_name = data.azurerm_virtual_network.tf-vn.name
resource_group_name = var.rg_name
}
module "sql_vm" {
source = "Azure/compute/azurerm"
location = data.azurerm_resource_group.tf-rg-external.location
vnet_subnet_id = data.azurerm_virtual_network.tf-vn.subnets
resource_group_name = data.azurerm_resource_group.tf-rg-external.name
admin_password = var.admin_password
admin_username = var.admin_username
boot_diagnostics = var.boot_diagnostics
boot_diagnostics_sa_type = var.boot_diagnostics_sa_type
# data_disk = var.data_disk
# data_disk_size_gb = var.data_disk_size_gb
# data_sa_type = var.data_sa_type
delete_os_disk_on_termination = var.delete_os_disk_on_termination
enable_accelerated_networking = var.enable_accelerated_networking
# flag is_windows_image is required only when you use a custom image to spin up a VM
# is_windows_image
# flag vm_os_id is required only when you are using custom image
# you need to provide id of your custom image
# vm_os_id
nb_instances = var.nb_instances
#nb_public_ip = var.nb_public_ip
public_ip_address_allocation = var.public_ip_address_allocation
storage_account_type = var.storage_account_type
vm_hostname = var.vm_hostname
vm_os_offer = var.vm_os_offer
vm_os_publisher = var.vm_os_publisher
# vm_os_simple is to be used is you do not wish to specify offer, publisher and sku
# vm_os_simple = UbuntuServer, WindowsServer, RHEL, openSUSE-Leap, CentOS, Debian, CoreOS and SLES
vm_os_sku = var.vm_os_sku
vm_os_version = var.vm_os_version
vm_size = var.vm_size
}
my variables.tf file is as below:
variable "public_ip_address_allocation" {
type = string
default = "Dynamic"
}
variable "storage_account_type" {
type = string
default = "Standard_LRS"
}
variable "vm_hostname" {
type = string
default = "testvm"
}
variable "vm_os_offer" {
type = string
default = "WindowsServer"
}
variable "vm_os_publisher" {
type = string
default = "MicrosoftWindowsServer"
}
variable "vm_os_sku" {
type = string
default = "2012-R2-Datacenter"
}
variable "vm_os_version" {
type = string
default = "latest"
}
variable "vm_size" {
type = string
default = "Standard_B1ms"
}
variable "admin_password" {
type = string
default = "Symphony12#$%"
}
variable "admin_username" {
type = string
default = "devopsadmin"
}
variable "boot_diagnostics" {
type = bool
default = "true"
}
variable "boot_diagnostics_sa_type" {
type = string
default = "Standard_LRS"
}
# variable "data_disk" {
# type = bool
# default ="false"
# }
# variable "data_disk_size_gb" {
# type = number
# default = 0
# }
# variable "data_sa_type" {
# type = string
# }
variable "delete_os_disk_on_termination" {
type = bool
default = true
}
variable "enable_accelerated_networking" {
type = bool
default = false
}
variable "nb_instances" {
type = number
default = 2
}
# variable "nb_public_ip" {
# type = bool
# default = "1"
# }
# variable "location" {
# type = string
# }
# variable "vnet_subnet_id" {
# type = string
# }
variable "rg_name" {
type = string
default = "nxt-grp-prd-manage-rgp-au-se"
}
variable "subnet_name" {
type = string
default = "subnet_1"
}
variable "vnet_name" {
type = string
default = "virtual_network_1"
}
When I run terraform plan, it reports Error below:
Refreshing Terraform state in-memory prior to plan...
The refreshed state will be used to calculate this plan, but will not be
persisted to local or remote state storage.
data.azurerm_virtual_network.tf-vn: Refreshing state...
data.azurerm_resource_group.tf-rg-external: Refreshing state...
data.azurerm_subnet.tf-sn: Refreshing state...
------------------------------------------------------------------------
Warning: "public_ip_address_allocation": [DEPRECATED] this property has been deprecated in favor of `allocation_method` to better match the api
on .terraform/modules/sql_vm/Azure-terraform-azurerm-compute-fb014dd/main.tf line 248, in resource "azurerm_public_ip" "vm":
248: resource "azurerm_public_ip" "vm" {
Warning: "public_ip_address_allocation": [DEPRECATED] this property has been deprecated in favor of `allocation_method` to better match the api
on .terraform/modules/sql_vm/Azure-terraform-azurerm-compute-fb014dd/main.tf line 248, in resource "azurerm_public_ip" "vm":
248: resource "azurerm_public_ip" "vm" {
Error: domain_name_label must contain only lowercase alphanumeric characters, numbers and hyphens. It must start with a letter and end only with a number or letter
on .terraform/modules/sql_vm/Azure-terraform-azurerm-compute-fb014dd/main.tf line 248, in resource "azurerm_public_ip" "vm":
248: resource "azurerm_public_ip" "vm" {
I would like to have an ability to override what it is in default module, something like below
domain_name_label = "false"
Unfortunately, when I do so in my main file, I get error like below:
Error: Unsupported argument
on main.tf line 48, in module "sql_vm":
48: domain_name_label = "false"
An argument named "domain_name_label" is not expected here.
So, is there not anyway to override, as this is an out-of-box configuration, I would be much happier to see it working.

Answer 1

I would like to have an ability to override what it is in default module, something like below
For that, the tf module should declare that as a variable. Your module Azure/compute/azurerm doesn't have a variable defined for domain_name_label.
Taking a step back and looking at your original issue: Look at the following block of code from this module:
https://github.com/Azure/terraform-azurerm-compute/blob/master/main.tf#L248
resource "azurerm_public_ip" "vm" {
count = "${var.nb_public_ip}"
name = "${var.vm_hostname}-${count.index}-publicIP"
location = "${var.location}"
resource_group_name = "${azurerm_resource_group.vm.name}"
public_ip_address_allocation = "${var.public_ip_address_allocation}"
domain_name_label = "${element(var.public_ip_dns, count.index)}"
tags = "${var.tags}"
}
Please set a value for public_ip_dns in your call to this module. That is expected to fix your issue.
Example:
(Note the line public_ip_dns = ["my-new-good-vm"]):
module "sql_vm" {
source = "Azure/compute/azurerm"
location = data.azurerm_resource_group.tf-rg-external.location
vnet_subnet_id = data.azurerm_virtual_network.tf-vn.subnets
resource_group_name = data.azurerm_resource_group.tf-rg-external.name
admin_password = var.admin_password
admin_username = var.admin_username
public_ip_dns = ["my-new-good-vm"]
boot_diagnostics = var.boot_diagnostics
boot_diagnostics_sa_type = var.boot_diagnostics_sa_type
# data_disk = var.data_disk
# data_disk_size_gb = var.data_disk_size_gb
# data_sa_type = var.data_sa_type
delete_os_disk_on_termination = var.delete_os_disk_on_termination
enable_accelerated_networking = var.enable_accelerated_networking
# flag is_windows_image is required only when you use a custom image to spin up a VM
# is_windows_image
# flag vm_os_id is required only when you are using custom image
# you need to provide id of your custom image
# vm_os_id
nb_instances = var.nb_instances
#nb_public_ip = var.nb_public_ip
public_ip_address_allocation = var.public_ip_address_allocation
storage_account_type = var.storage_account_type
vm_hostname = var.vm_hostname
vm_os_offer = var.vm_os_offer
vm_os_publisher = var.vm_os_publisher
# vm_os_simple is to be used is you do not wish to specify offer, publisher and sku
# vm_os_simple = UbuntuServer, WindowsServer, RHEL, openSUSE-Leap, CentOS, Debian, CoreOS and SLES
vm_os_sku = var.vm_os_sku
vm_os_version = var.vm_os_version
vm_size = var.vm_size
}