variable "foo" { default = "bar" description = "bar" } variable "amis" { default = { east = "foo" } } provider "aws" { access_key = "foo" secret_key = "bar" } provider "do" { api_key = "${var.foo}" } resource "aws_security_group" "firewall" { } resource aws_instance "web" { ami = "${var.amis.east}" security_groups = [ "foo", "${aws_security_group.firewall.foo}" ] network_interface { device_index = 0 description = "Main network interface" } depends_on = ["aws_security_group.firewall"] }