deploy a ec2 and join into domain with terraform

Below is the example to convert the ps script into userdata for terraform to create instance and auto join domain.  But to make it work, we need to create a new DHCP options set for related VPC and have the domain-name= domain.com and domain-name-servers =  IP-of-the-domain-controllers .  so default DNS servers for new instance in that VPC will be domain controllers.  

resource "aws_instance" "example" {
  ami           = "${lookup(var.amis, var.region)}"
  instance_type = "t2.micro"
  subnet_id     = "subnet-fe179a00"
  vpc_security_group_ids      = ["sg-b93c9100"]
  key_name       = "newkey"
  provisioner "local-exec" {
    command = "echo ${aws_instance.example.public_ip} > ip_address.txt"
  }
  user_data = "<powershell>$Domain = 'domain.com'; $Username = 'domain\admin' ; $Password = 'xxxxxxxx' ; $pwd = $Password | ConvertTo-SecureString -asPlainText -Force ;  $credential = New-Object System.Management.Automation.PSCredential($UserName,$pwd) ;Add-Computer -DomainName $Domain -Credential $credential -Restart</powershell>"
}