how to create a Terraform for_each loop for number of virtual machines in Azure availability set

Question

We could create multiple azure vms in a availability set using "count" loop.

How can we create the same using "for_each" loop where the hostname and network interfaceid will be dynamic and looped over. (in terrraform > 0.12.6)

resource "azurerm_virtual_machine" "test" {

 # user provides inputs only for the number of vms to be created in the Azure avaialibility set

 count                 = var.count 
 name                  = "acctvm${count.index}"
 location              = azurerm_resource_group.test.location
 availability_set_id   = azurerm_availability_set.avset.id
 resource_group_name   = azurerm_resource_group.test.name
 network_interface_ids = [element(azurerm_network_interface.test.*.id, count.index)]
 vm_size               = "Standard_DS1_v2"
 tags                  = var.tags

Answer 1

You can specify the VM properties required in an object list, and then use a for_each loop like so:

variable "VirtualMachines" {
  type = list(object({
    hostname= string
    interfaceid = string 
  }))
  default = [
    {
        hostname= "VM01",
        interfaceid = "01"
    },
     {
        hostname= "VM02",
        interfaceid = "02"
    }
  ]
}
    
resource "azurerm_virtual_machine" "test" {

  for_each = {for vm in var.VirtualMachines: vm.hostname => vm}

  name =  each.value.hostname
  location = azurerm_resource_group.test.location
  availability_set_id = azurerm_availability_set.avset.id
  resource_group_name = azurerm_resource_group.test.name
  network_interface_ids = [each.value.interfaceid]
  vm_size = "Standard_DS1_v2"
  tags = var.tags
}