variable "foo" { default = "bar" description = "bar" } provider "aws" { test_string = "${openstack_floating_ip.random.test_string}" } resource "openstack_floating_ip" "random" {} resource "aws_security_group" "firewall" {} resource "aws_instance" "web" { test_string = var.foo test_list = [ "foo", aws_security_group.firewall.test_string, ] } resource "aws_load_balancer" "weblb" { test_list = aws_instance.web.test_list } locals { instance_id = "${aws_instance.web.test_string}" } output "instance_id" { value = "${local.instance_id}" }