Terraform script to build out the AWS environment for a node app

main.tf

variable "access_key" {}
variable "secret_key" {}

provider "aws" {
 access_key = "${var.access_key}"
 secret_key = "${var.secret_key}"
 region = "us-east-1"
}

data "aws_ami" "node_app_ami" {
 most_recent = true

filter {
 name = "name"
 values = ["packer-viresh-*"]
 }

filter {
 name = "virtualization-type"
 values = ["hvm"]
 }

owners = ["439988962471"]
}

resource "aws_launch_configuration" "node_app_lc" {
 image_id = "${data.aws_ami.node_app_ami.id}"
 instance_type = "t2.micro"
 security_groups = ["${aws_security_group.node_app_websg.id}"]
 lifecycle {
 create_before_destroy = true
 }
}

resource "aws_autoscaling_group" "node_app_asg" {
 name = "terraform-asg-node-app-${aws_launch_configuration.node_app_lc.name}"
 launch_configuration = "${aws_launch_configuration.node_app_lc.name}"
 availability_zones = ["${data.aws_availability_zones.allzones.names}"]
 min_size = 1
 max_size = 2

load_balancers = ["${aws_elb.elb1.id}"]
 health_check_type = "ELB"

lifecycle {
 create_before_destroy = true
 }
}

resource "aws_security_group" "node_app_websg" {
 name = "security_group_for_node_app_websg"
 ingress {
 from_port = 3000
 to_port = 3000
 protocol = "tcp"
 cidr_blocks = ["0.0.0.0/0"]
 }

lifecycle {
 create_before_destroy = true
 }
}

resource "aws_security_group" "elbsg" {
 name = "security_group_for_elb"
 ingress {
 from_port = 3000
 to_port = 3000
 protocol = "tcp"
 cidr_blocks = ["0.0.0.0/0"]
 }

egress {
 from_port = 0
 to_port = 0
 protocol = "-1"
 cidr_blocks = ["0.0.0.0/0"]
 }

lifecycle {
 create_before_destroy = true
 }
}

data "aws_availability_zones" "allzones" {}

resource "aws_elb" "elb1" {
 name = "terraform-elb-node-app"
 availability_zones = ["${data.aws_availability_zones.allzones.names}"]
 security_groups = ["${aws_security_group.elbsg.id}"]

listener {
 instance_port = 3000
 instance_protocol = "http"
 lb_port = 3000
 lb_protocol = "http"
 }

health_check {
 healthy_threshold = 2
 unhealthy_threshold = 2
 timeout = 3
 target = "HTTP:3000/"
 interval = 30
 }

cross_zone_load_balancing = true
 idle_timeout = 400
 connection_draining = true
 connection_draining_timeout = 400

tags {
 Name = "terraform - elb - node-app"
 }
}