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daks
Asked: 2020-03-21 07:05:45 +0800 CST

Terraform: output IP of all my different servers

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I'm starting to use Terraform (0.12) with different types of servers, each associated to a different image. I'm trying to simply output all private IP (I don't know the number before runtime) but can't find a simple way to do it (I found a more complicated one).

I'm trying TF on scaleway provider and I have some servers declaration like this (simplified)

# INPUT
variable "srv1" {
  type        = number
  default     = 0
}
variable "srv2" {
  type        = number
  default     = 0
}

# IMAGES
data "scaleway_instance_image" "srv1" {
  name = "srv1"
}
data "scaleway_instance_image" "srv2" {
  name = "srv2"
}

# SERVERS
resource "scaleway_instance_server" "srv1" {
  name              = "srv1_${count.index}"
  image             = data.scaleway_instance_image.srv1.id
  count             = var.srv1
}
resource "scaleway_instance_server" "srv2" {
  name              = "srv2_${count.index}"
  image             = data.scaleway_instance_image.srv2.id
  count             = var.srv2
}

To output private IP from all servers, this is what I do

# OUTPUT
output "srv1_private_ips" {
  value = ["${scaleway_instance_server.srv1.*.private_ip}"]
}

output "srv2_private_ips" {
  value = ["${scaleway_instance_server.srv2.*.private_ip}"]
}

It works but I need to create an output section for each server type. I would like to have the option

  • to loop over a list of server types and output all IPs in one output. Didn't find how
  • to just output all scaleway_instance_server.*.*.private_ip but the double wildcard seems not possible

Any help appreciated.

terraform scaleway

1 Answers

  1. You have a bit of a misunderstanding of how "count" and the splat ("*") syntax work. Using count, you will create a single resource block for your servers, using count to define how many times that instance will be duplicated. Hence:

    resource "scaleway_instance_server" "srv" {
  name              = "srv_${count.index}"
  image             = data.scaleway_instance_image.srv1.id
  count             = 2
}

    Will create two resources: scaleway_instance_server.srv[0] and scaleway_instance_server.srv[1]. (Yes, they'll have the same image - that's a hint that this probably isn't the best way to manage this)

    Outputting a list of the private_ip attribute from all of the servers becomes trivial:

    output "srv_private_ips" {
  value = scaleway_instance_server.srv[*].private_ip
}

    NOTE: I've never used the scaleway provider in the example you gave, so I'm just guessing that attribute exists

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