gistfile1.txt

# iops
resource "aws_db_instance" "rds" {
    identifier           = "${var.identifier}"
    allocated_storage    = "${var.allocated_storage}"
    iops                 = "${var.iops}"
    engine               = "${var.engine}"
    engine_version       = "${var.engine_version}"
    instance_class       = "${var.instance_class}"
    name                 = "${var.db_name}"
    username             = "${var.db_username}"
    password             = "${var.db_password}"
    db_subnet_group_name = "${var.db_subnet_group_name}"
    parameter_group_name = "${var.parameter_group_name}"
    vpc_security_group_ids = ["${split(",", var.vpc_security_group_ids)}"]
}

#non iops
resource "aws_db_instance" "rds" {
    identifier           = "${var.identifier}"
    allocated_storage    = "${var.allocated_storage}"
    storage_type         = "${var.storage_type}"
    engine               = "${var.engine}"
    engine_version       = "${var.engine_version}"
    instance_class       = "${var.instance_class}"
    name                 = "${var.db_name}"
    username             = "${var.db_username}"
    password             = "${var.db_password}"
    db_subnet_group_name = "${var.db_subnet_group_name}"
    parameter_group_name = "${var.parameter_group_name}"
    vpc_security_group_ids = ["${split(",", var.vpc_security_group_ids)}"]
}

#elb non-ssl
resource "aws_elb" "elb" {
  name            = "${var.elb_name}"
  subnets         = ["${split(",", var.subnet_azs)}"]
  internal        = "${var.elb_is_internal}"
  security_groups = ["${var.elb_security_group}"]

  listener {
    instance_port      = "${var.backend_port}"
    instance_protocol  = "${var.backend_protocol}"
    lb_port            = "${var.lb_port}"
    lb_protocol        = "${var.lb_protocol}"
  }

  health_check {
    healthy_threshold   = 2
    unhealthy_threshold = 2
    timeout             = 3
    target              = "${var.health_check_target}"
    interval            = 30
  }

  cross_zone_load_balancing = true
}

#elb ssl
resource "aws_elb" "elb" {
  name            = "${var.elb_name}"
  subnets         = ["${split(",", var.subnet_azs)}"]
  internal        = "${var.elb_is_internal}"
  security_groups = ["${var.elb_security_group}"]

  listener {
    instance_port      = "${var.backend_port}"
    instance_protocol  = "${var.backend_protocol}"
    lb_port            = "${var.lb_port}"
    lb_protocol        = "${var.lb_protocol}"
    ssl_certificate_id = "${var.ssl_certificate_id}"
  }

  health_check {
    healthy_threshold   = 2
    unhealthy_threshold = 2
    timeout             = 3
    target              = "${var.health_check_target}"
    interval            = 30
  }

  cross_zone_load_balancing = true
}

For the ELB example, another variant is whether or not you want the access logs stored in an S3 bucket.