efs-efs.tf

resource "aws_efs_file_system" "filesystem" {
  creation_token = "${var.efs_name}"
}

resource "aws_efs_mount_target" "fs_target" {
  file_system_id = "${aws_efs_file_system.filesystem.id}"
  subnet_id = "${var.subnet_id}"
  security_groups = ["${var.vpc_sg_ids}"]
}

output "efs_id" { value = "${aws_efs_file_system.filesystem.id}" }
output "net_id" { value = "${aws_efs_file_system.filesystem.network_interface_id}" }

efs-variables.tf

# Network & Region
variable "subnet_id" {}
variable "vpc_sg_ids" {}

# Name
variable "efs_name" {}

main.snippet.tf

# EFS
module "filesystem" {
  source = "./efs"
  
  efs_name = "${var.efs_name}"
  vpc_sg_ids = "${var.vpc_sg_ids}"
  subnet_id = "${var.subnet_id}"
}

variables.snippet.tf

# Location and Network =====================================
variable "subnet_id" { default = "<subnet-id>" }
variable "vpc_sg_ids" { default = "<security-group-ids>" }   

# EFS ======================================================
# Name
variable "efs_name" { default = "cluster-tut-efs" }