How to Import an Azure Linux VM Scale Set into Terraform

Import Azure Linux VM Scale Set with Terraback (recommended)

Terraback reverse-engineers your live infrastructure: it reads the Azure Compute resource with read-only credentials, generates the HCL, and produces the exact import block. Two commands take you from a live Azure Linux VM Scale Set to managed Terraform.

terraback scan all azure --subscription-id YOUR_ID

terraback azure import --method bulk

The Terraform import block

Terraback emits a Terraform 1.5+ import block like the one below. Because the block lives in your configuration, the import is reviewable in a pull request and repeatable across environments.

import {
  to = azurerm_linux_virtual_machine_scale_set.web
  id = "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/prod-rg/providers/Microsoft.Compute/virtualMachineScaleSets/web-vmss"
}

Example azurerm_linux_virtual_machine_scale_set configuration

Here is a realistic Azure Linux VM Scale Set block. Terraback generates a fuller version from your actual resource attributes; this is a minimal, valid starting point.

resource "azurerm_linux_virtual_machine_scale_set" "web" {
  name                = "web-vmss"
  location            = "eastus"
  resource_group_name = "prod-rg"
  sku                 = "Standard_B2s"
  instances           = 3
  admin_username      = "azureuser"

  source_image_reference {
    publisher = "Canonical"
    offer     = "0001-com-ubuntu-server-jammy"
    sku       = "22_04-lts"
    version   = "latest"
  }

  os_disk {
    caching              = "ReadWrite"
    storage_account_type = "Standard_LRS"
  }

  network_interface {
    name    = "primary"
    primary = true

    ip_configuration {
      name      = "internal"
      primary   = true
      subnet_id = azurerm_subnet.internal.id
    }
  }
}

Gotchas when importing a Azure Linux VM Scale Set

• Azure splits scale sets by OS: use azurerm_linux_virtual_machine_scale_set, not the deprecated azurerm_virtual_machine_scale_set.
• Admin passwords and SSH keys are never returned by Azure; supply admin_ssh_key or admin_password in code or set disable_password_authentication.
• Individual VM instances are managed by the scale set; do not import them as standalone VMs.
• Autoscaling lives in a separate azurerm_monitor_autoscale_setting that targets this scale set's ID.

Doing it manually with terraform import

The native approach is to write the azurerm_linux_virtual_machine_scale_set block by hand, then run terraform import azurerm_linux_virtual_machine_scale_set.example <import-id> for every resource, one at a time. That works for a handful of resources, but it does not scale: you author all the HCL yourself and repeat the command for each item. Terraback generates the HCL and the import blocks for your whole account in one pass.

Import other Azure resources