gistfile1.txt

### autoscale.tf

data "template_file" "userdata" {
    template = "${file("templates/userdata.tpl")}"
    vars {
        region            = "${var.region}"
        file_system_id    = "${aws_efs_file_system.prod-efs.id}"
    }
}
resource "aws_launch_configuration" "mig5-prod-lc" {
  # <snip..>
  user_data               = "${data.template_file.userdata.rendered}"
}

### templates/userdata.tpl

#cloud-config
package_upgrade: false
runcmd:
- echo "$(curl -s http://169.254.169.254/latest/meta-data/placement/availability-zone).${file_system_id}.efs.${region}.amazonaws.com:/    /var/www/shared   nfs    defaults,vers=4.1 0 0" >> /etc/fstab
- mount -a