Get Private IP from ASG - amazon-web-services

Question

I need to output private IP from Auto Scaling Group of EC2 instance that configuration by Terraform. How can i get private IP from ASG?
# Launch config for ASG
resource "aws_launch_configuration" "asg_conf" {
name = "ASG-Conf-${var.env}"
image_id = data.aws_ami.ubuntu.id # Get image from data
instance_type = var.instance_type # use t2.micro ad default
security_groups = [var.sg_app.id, var.sg_alb.id] # SG for APP
key_name = var.ssh_key # SSH key for connection to EC2
user_data = file("./modules/ec2/shell/apache.sh") # install apache
lifecycle {
create_before_destroy = true
}
}
# Auto Scaling Group
resource "aws_autoscaling_group" "asg" {
count = length(var.private_subnet_id) # count numbers of private subnets
name = "ASG-${var.env}-${count.index + 1}"
vpc_zone_identifier = [var.private_subnet_id[count.index]]
launch_configuration = aws_launch_configuration.asg_conf.name
target_group_arns = [var.alb_target.arn]
min_size = 1 # Min size of creating EC2
max_size = 1 # Max size of creating EC2
health_check_grace_period = 120
health_check_type = "ELB"
force_delete = true
lifecycle {
create_before_destroy = true
}
tag {
key = "Name"
value = "Webserver-ec2-${count.index + 1}"
propagate_at_launch = true
}
}
output {
# How can i get this???
value = aws_autoscaling_group.asg.private_ip
}
My infrastructure create 1 EC2 instance in 2 private AZ by ASG and i need output IP from this ASG

Answer 1

You need custom data source to get the IPs. But this really does not make much sense as instances in ASG can be changed by AWS at any time, thus making your IPs obsolete.