first run missing output

main.tf

provider "scaleway" {}

variable "commercial_type" {
  default = "C1"
}

variable "architectures" {
  default = {
    C1   = "arm"
    VC1S = "x86_64"
    VC1M = "x86_64"
    VC1L = "x86_64"
    C2S  = "x86_64"
    C2M  = "x86_64"
    C2L  = "x86_64"
  }
}

data "scaleway_image" "ubuntu" {
  architecture = "${lookup(var.architectures, var.commercial_type)}"
  name = "Ubuntu Xenial"
}

resource "scaleway_server" "node" {
   count          = "2"
   name           = "cluser-node-${count.index + 1}"
   image          = "${data.scaleway_image.ubuntu.id}"
   type           = "${var.commercial_type}"
   tags           = ["TEST"]
}

resource "scaleway_ip" "public_ip" {
   count  = "2"
   server = "${element(scaleway_server.node.*.id, count.index)}"
}

output "public_ips" {
  value = "${scaleway_server.node.*.public_ip}"
}