如何从 terraform 创建 ansible 库存？

Question

I relay stack with that simple question.

Assume i need create few instance resources so how can i iterate from from tf variables to gather all private ips and pass it to ansible inventory file.

As i found i have to use * like here:

k8s_master_name = "${join("\n", azurerm_virtual_machine.k8s-master.*.name)}"

But i as think for me it will look like:

inst_ip = "${join("\n", ${aws_instance.*.private_ip})}"

But i got error:

Error: Invalid reference
 on crc.cloud.connect.tf line 72, in resource "local_file" "servers1":
 72:       inst_ip = "${join("\n", aws_instance.*.private_ip)}"
  
 A reference to a resource type must be followed by at least one attribute
 access, specifying the resource name.

Full tf file:

  resource "aws_instance" "sp-1" {
  ami               = "cmi-993E674A"
  instance_type     = "c5.large"
  monitoring        = true
  source_dest_check = false
  user_data         = file("user_data.sh")
  subnet_id              = "subnet-F6C45280"
  private_ip             = "172.31.16.18"
  vpc_security_group_ids = ["sg-230C7615"]
  key_name = "mmk-key"
  #network_interface {
  #  network_interface_id = "${aws_network_interface.ni-sp-1.id}"
  #  device_index         = 0
  #}
  tags = {
    desc = "sp-1"  
    group_name = "sp"
  }

}

  resource "aws_instance" "sp-2" {
  ami               = "cmi-993E674A"
  instance_type     = "c5.large"
  monitoring        = true
  source_dest_check = false
  user_data         = file("user_data.sh")
  subnet_id              = "subnet-F6C45280"
  private_ip             = "172.31.16.19"
  vpc_security_group_ids = ["sg-230C7615"]
  key_name = "mmk-key"
  tags = {
    desc = "sp-2"  
    group_name = "sp"

  }
}

resource "local_file" "servers1" {
  content = templatefile("${path.module}/templates/servers1.tpl",
    {
      inst_ip = "${join("\n", ${aws_instance.*.private_ip})}"
    }
  )
  filename = "../ansible/inventory/servers1"
}

Answer 1

Per the Terraform documentation , you need to reference the resource type and its associated name.

In your configuration file, you have an aws_instance resource with the name sp-1 . If you wish to access the private_ip attribute of the resource, you need to do it like so: aws_instance.sp-1[*].private_ip .

Answer 2

You are creating a single instance aws_instance.sp-1 , not multiple instances. To create multiple instance you would need to use count or for_each , or provision instances through aws_autoscaling_group .

Therefore, to access private_ip you don't really need splat * and join in your case (but still can use them if you want) as you have only one instance and will have only one private_ip . The following should be enough instead:

inst_ip = aws_instance.sp-1.private_ip