VM Scale Set fails if computer_name_prefix is greater than 9 characters

[PleaseStopAsking]

Terraform Version

Terraform v0.11.3

• provider.azurerm v1.1.2
• provider.random v1.1.0

Affected Resource(s)

• azurerm_virtual_machine_scale_set

Terraform Configuration Files

variable "customerProject" {
    default = "apphst"
}

variable "environment" {
    default = "stg"
}

variable "machineAcronyms" {
    default = {
	Server = "ags"
	Jumpbox	= "jmp"
    }
}

resource "azurerm_virtual_machine_scale_set" "ServerScaleSet" {
    name = "${var.customerProject}${var.environment}${var.machineAcronyms["Server"]}"
    location = "${var.location}"
    resource_group_name = "${azurerm_resource_group.rg.name}"
    upgrade_policy_mode	= "Manual"

    sku {
        name = "${var.Server_Specs["ServerType"]}"
    	tier = "Standard"
    	capacity = 1
    }

    storage_profile_image_reference {
        publisher = "${var.Server_Specs["Image_Publisher"]}"
        offer = "${var.Server_Specs["Image_Offer"]}"
	sku = "${var.Server_Specs["Image_sku"]}"
	version = "${var.Server_Specs["Image_Version"]}"
    }

    plan {
	name = "${var.Server_Specs["Plan_Name"]}"
	publisher = "${var.Server_Specs["Plan_Publisher"]}"
	product = "${var.Server_Specs["Plan_Product"]}"
    }

    storage_profile_os_disk {
	name = ""
	managed_disk_type = "${var.Server_Specs["OS_Disk_Type"]}"
	caching = "${var.Server_Specs["OS_Disk_Caching"]}"
	create_option = "${var.Server_Specs["OS_Disk_Create_option"]}"
    }

    storage_profile_data_disk {
	managed_disk_type = "${var.Server_Specs["Data_Disk_Type"]}"
	caching = "${var.Server_Specs["Data_Disk_Caching"]}"
	create_option = "${var.Server_Specs["Data_Disk_Create_Option"]}"
	disk_size_gb = "${var.Server_Specs["Data_Disk_Disk_Size"]}"
	lun = "${var.Server_Specs["Data_Disk_Disk_Lun"]}"
    }

    os_profile {
	computer_name_prefix = "${var.customerProject}${var.environment}${var.machineAcronyms["Server"]}"
	admin_username = "${var.EmcsAdminCredentials["Username"]}"
	admin_password = "${var.EmcsAdminCredentials["Password"]}"
    }

    os_profile_windows_config {
	provision_vm_agent  = "true"
    }

    network_profile {
	name = "${var.customerProject}${var.environment}${var.machineAcronyms["Server"]}"
	primary = true

	ip_configuration {
	    name = "${var.customerProject}${var.environment}${var.machineAcronyms["Server"]}"
	    subnet_id   = "${azurerm_subnet.PrivateSubnet.id}"
	}
    }
}

Expected Behavior

The template should succeed.

Actual Behavior

The template fails with the following message.

azurerm_virtual_machine_scale_set.ServerScaleSet: 1 error(s) occurred:

* azurerm_virtual_machine_scale_set.ServerScaleSet: compute.VirtualMachineScaleSetsClient#CreateOrUpdate: Failure sending request: StatusCode=400 -- Original Error: autorest/azure: Service returned an error. Status=400 Code="InvalidParameter" Message="Windows computer name prefix cannot be more than 9 characters long, be entirely numeric, or contain the following characters: ` ~ ! @ # $
% ^ & * ( ) = + _ [ ] { } \\ | ; : . ' \" , < > / ?. Provided computer name prefix: apphststgags."

Important Factoids

The online docs indicate that the length should be between 1-15 characters.
https://www.terraform.io/docs/providers/azurerm/r/virtual_machine_scale_set.html#computer_name_prefix

[PleaseStopAsking]

Hi @tombuildsstuff

Is this an issue with the documentation not correctly showing the number of characters or an issue with terraform not allowing 15 characters?

Thanks,

[katbyte]

Hello @PleaseStopAsking,

This is an issue with the documentation. Windows hosts are limited to a 9 character prefix while linux ones can go up to 58 characters.

Thank you for pointing it out! I will go and correct it today.

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

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