VM scale set recreated everytime if custom_data used

[r7vme]

I have scale set with custom_data. On every terraform run scale set gets recreated.

Terraform Version

Terraform v0.10.8

Affected Resource(s)

Please list the resources as a list, for example:

• azurerm_virtual_machine_scale_set

Terraform Configuration Files

Just picked one from documentation and added custom_data

resource "azurerm_resource_group" "test" {
  name     = "roman-test-vmss"
  location = "westeurope"
}

resource "azurerm_virtual_network" "test" {
  name                = "acctvn"
  address_space       = ["10.0.0.0/16"]
  location            = "westeurope"
  resource_group_name = "${azurerm_resource_group.test.name}"
}

resource "azurerm_subnet" "test" {
  name                 = "acctsub"
  resource_group_name  = "${azurerm_resource_group.test.name}"
  virtual_network_name = "${azurerm_virtual_network.test.name}"
  address_prefix       = "10.0.2.0/24"
}

resource "azurerm_public_ip" "test" {
  name                         = "test"
  location                     = "westeurope"
  resource_group_name          = "${azurerm_resource_group.test.name}"
  public_ip_address_allocation = "static"
  domain_name_label            = "${azurerm_resource_group.test.name}"

  tags {
    environment = "staging"
  }
}

resource "azurerm_lb" "test" {
  name                = "test"
  location            = "westeurope"
  resource_group_name = "${azurerm_resource_group.test.name}"

  frontend_ip_configuration {
    name                 = "PublicIPAddress"
    public_ip_address_id = "${azurerm_public_ip.test.id}"
  }
}

resource "azurerm_lb_backend_address_pool" "bpepool" {
  resource_group_name = "${azurerm_resource_group.test.name}"
  loadbalancer_id     = "${azurerm_lb.test.id}"
  name                = "BackEndAddressPool"
}

resource "azurerm_lb_nat_pool" "lbnatpool" {
  count                          = 3
  resource_group_name            = "${azurerm_resource_group.test.name}"
  name                           = "ssh"
  loadbalancer_id                = "${azurerm_lb.test.id}"
  protocol                       = "Tcp"
  frontend_port_start            = 50000
  frontend_port_end              = 50119
  backend_port                   = 22
  frontend_ip_configuration_name = "PublicIPAddress"
}

resource "azurerm_virtual_machine_scale_set" "test" {
  name                = "mytestscaleset-1"
  location            = "westeurope"
  resource_group_name = "${azurerm_resource_group.test.name}"
  upgrade_policy_mode = "Manual"

  sku {
    name     = "Standard_A0"
    tier     = "Standard"
    capacity = 2
  }

  storage_profile_image_reference {
    publisher = "Canonical"
    offer     = "UbuntuServer"
    sku       = "16.04-LTS"
    version   = "latest"
  }

  storage_profile_os_disk {
    name              = ""
    caching           = "ReadWrite"
    create_option     = "FromImage"
    managed_disk_type = "Standard_LRS"
  }

  storage_profile_data_disk {
      lun          = 0
    caching        = "ReadWrite"
    create_option  = "Empty"
    disk_size_gb   = 10
  }

  os_profile {
    computer_name_prefix = "testvm"
    admin_username       = "myadmin"
    admin_password       = "Passwword1234"
    custom_data = "${base64encode("${file("cloud-config")}")}"
  }

  os_profile_linux_config {
    disable_password_authentication = true

    ssh_keys {
      path     = "/home/myadmin/.ssh/authorized_keys"
      key_data = "${file("~/.ssh/id_rsa.pub")}"
    }
  }

  network_profile {
    name    = "terraformnetworkprofile"
    primary = true

    ip_configuration {
      name                                   = "TestIPConfiguration"
      subnet_id                              = "${azurerm_subnet.test.id}"
      load_balancer_backend_address_pool_ids = ["${azurerm_lb_backend_address_pool.bpepool.id}"]
      load_balancer_inbound_nat_rules_ids    = ["${element(azurerm_lb_nat_pool.lbnatpool.*.id, count.index)}"]
    }
  }

  tags {
    environment = "staging"
  }
}

Debug Output

terraform plan

Expected Behavior

Resource updated w/o recreation.

Actual Behavior

Resource recreated.

Steps to Reproduce

1. terraform apply
2. terraform plan

References

Discussion here can also be related.

[r7vme]

Anyone can please take a look?

[bugblatter2016]

We are seeing exactly the same problem here. Terraform v0.10.8 and AzureRM provider v0.3.2_x4.

[samirageb]

Can also confirm running into this for TF 0.10.8, latest AzureRM 0.3.2

[samirageb]

Bump. This is an incredibly disruptive bug.

[tombuildsstuff]

@samirageb @r7vme @bugblatter2016 thanks for reporting this issue - apologies for the delay looking into this! I'm taking a look at this now

[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.

If you feel this issue should be reopened, we encourage creating a new issue linking back to this one for added context. If you feel I made an error 🤖 🙉 , please reach out to my human friends 👉 hashibot-feedback@hashicorp.com. Thanks!