title: how to use custom_data field of azurerm_virtual_machine resource in terraform?
body: <p>I am trying to use custom_data field of resource azurerm_virtual_machine, but getting caught up into this error. Any idea what I am missing or is that a wrong usage?</p>
  
  <pre><code>resource "azurerm_virtual_machine" "csrVM" {
    name                  = "csr-terraform-poc"
    location              = "${var.location}"
    resource_group_name   = "${azurerm_resource_group.terraformRG.name}"
    network_interface_ids = ["${azurerm_network_interface.terraformNic1.id}",
                             "${azurerm_network_interface.terraformNic2.id}"]
    primary_network_interface_id = "${azurerm_network_interface.terraformNic1.id}"
    vm_size               = "Standard_DS1_v2"
  
    custom_data = "${file("customdata.txt")}"
    #custom_data = &lt;&lt;CUSTOMDATA
    #username testuser privilege 15 password testpass
    #enable password testpass
  #CUSTOMDATA
  </code></pre>
  
  <p>~>terraform apply -var-file=azure.tfvars</p>
  
  <p><strong>Error: azurerm_virtual_machine.csrVM: : invalid or unknown key: custom_data</strong></p>
  
  <p>~>terraform -v
  Terraform v0.11.3
  + provider.azurerm v1.1.1</p>