How to effectively use azure_virtual_machine_extension in Azure Terraform

Question

I'd like to run multiple linux commands using azurerm_virtual_machine_extension. Is there a sophisticated way to use multiple commands side by side instead of listing them in a single line? I've previously used it as below.

resource "azurerm_virtual_machine_extension" "run_command" {
  for_each             = var.vm_template
  name                 = "${each.value.vm_name}-run_command"
  virtual_machine_id   = azurerm_linux_virtual_machine.vm[each.key].id
  publisher            = "Microsoft.Azure.Extensions"
  type                 = "CustomScript"
  type_handler_version = "2.0"
  timeouts {
    create = "1h" # VM 개수가 많으면 그만큼 더 오래걸림
  }
  settings = <<SETTINGS
 {
  "commandToExecute": "bash -c 'hostnamectl set-hostname --static ${each.value.hostname}'&& sleep 60 && sh /tmp/for_image.sh > /tmp/installed.log 2>&1"
 }
SETTINGS
}

Is it possible to write a code by aligning it line by line without executing all the commands line like above? I need your help.

Answer 1

How to effectively use azure_virtual_machine_extension in Azure Terraform

Here is the Terraform code to create multiple vms and multilple cmd's with VM extensions for executing Bash code inside the VMs.

variables.tf

variable "vms" {
  default = [
    {
      name   = "vm1"
      size   = "Standard_DS1_v2"
      admin_username = "Venkat"
      admin_password = "Welcome@123$"
      computer_name   = "Linux_VM1"
      new_computername = "Venkat_LinuxVM1"
    },
    {
      name   = "vm2"
      size   = "Standard_DS1_v2"
      admin_username = "Venkat"
      admin_password = "Welcome@123$"
      computer_name   = "Linux_VM2"
      new_computername = "Venkat_LinuxVM2"
    }
  ]
}

main.tf

provider "azurerm" {
  features {}
}

resource "azurerm_resource_group" "example" {
  name     = "VM-resources"
  location = "West US"
}

resource "azurerm_virtual_network" "example" {
  name                = "example-network"
  address_space       = ["10.0.0.0/16"]
  location            = azurerm_resource_group.example.location
  resource_group_name = azurerm_resource_group.example.name
}

resource "azurerm_subnet" "example" {
  name                 = "sample"
  resource_group_name  = azurerm_resource_group.example.name
  virtual_network_name = azurerm_virtual_network.example.name
  address_prefixes     = ["10.0.2.0/24"]
}

resource "azurerm_public_ip" "example" {
  count               = 2
  name                = "demo-pip-${count.index}"
  location            = azurerm_resource_group.example.location
  resource_group_name = azurerm_resource_group.example.name
  allocation_method   = "Static"
}

resource "azurerm_network_interface" "example" {
  count               = 2
  name                = "demo-nic-${count.index}"
  location            = azurerm_resource_group.example.location
  resource_group_name = azurerm_resource_group.example.name

  ip_configuration {
    name                          = "internal"
    subnet_id                     = azurerm_subnet.example.id
    private_ip_address_allocation = "Dynamic"
    public_ip_address_id          = element(azurerm_public_ip.example.*.id, count.index)
  }
}

resource "azurerm_linux_virtual_machine" "example" {
  count              = length(var.vms)
  name               = var.vms[count.index].name
  location           = azurerm_resource_group.example.location
  resource_group_name = azurerm_resource_group.example.name
  size               = var.vms[count.index].size
  admin_username     = var.vms[count.index].admin_username
  network_interface_ids = [
    azurerm_network_interface.example[count.index].id,
  ]

  computer_name      = var.vms[count.index].computer_name
  admin_password     = var.vms[count.index].admin_password
  disable_password_authentication = false

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

  source_image_reference {
    publisher = "Canonical"
    offer     = "UbuntuServer"
    sku       = "18.04-LTS"
    version   = "latest"
  }
}

  resource "azurerm_virtual_machine_extension" "hostname" {
  count               = length(var.vms)
  name                = "hostname"
  virtual_machine_id  = azurerm_linux_virtual_machine.example[count.index].id
  publisher           = "Microsoft.Azure.Extensions"
  type                = "CustomScript"
  type_handler_version = "2.0"
  
      settings = <<SETTINGS
        fileUris = [
          "https://samplestoragevm.blob.core.windows.net/vmstorage/script.sh",
        ]
        commandToExecute = "sh script.sh"
}

Terraform apply

After executing the VM Extension, the hostname was changed successfully.

VM 1 Hostname:

Update:

To run multiple commands using azurerm_virtual_machine_extension, create a bash file and upload the same file to a storage account. Then, use the blob URL in fileUris in terraform.

   resource "azurerm_virtual_machine_extension" "hostname" {
  count               = length(var.vms)
  name                = "hostname"
  virtual_machine_id  = azurerm_linux_virtual_machine.example[count.index].id
  publisher           = "Microsoft.Azure.Extensions"
  type                = "CustomScript"
  type_handler_version = "2.0"
  
      settings = <<SETTINGS
        fileUris = [
          "https://samplestoragevm.blob.core.windows.net/vmstorage/script.sh",
        ]
        commandToExecute = "sh script.sh"
}

Reference: Stack link1 by Nancy and link2 answered by me for using multiple commands in azurerm_virtual_machine_extension.

Custom Script Extension