Working terraform with flatcar on digitalocean.

cl/machine-mynode.yaml.tmpl

@@ -0,0 +1,18 @@
+---
+variant: flatcar
+version: 1.1.0
+passwd:
+  users:
+    - name: core
+      ssh_authorized_keys: ${ssh_keys}
+storage:
+  files:
+    - path: /home/core/works
+      mode: 0755
+      contents:
+        inline: |
+          #!/bin/bash
+          set -euo pipefail
+          # This script demonstrates how templating and variable substitution works when using Terraform templates for Container Linux Configs.
+          hostname="$(hostname)"
+          echo My name is ${name} and the hostname is $${hostname} and this is updated!

main.tf

@@ -4,6 +4,18 @@ terraform {
       source  = "digitalocean/digitalocean"
       version = "2.62.0"
     }
+    ct = {
+      source  = "poseidon/ct"
+      version = "0.13.0"
+    }
+    template = {
+      source  = "hashicorp/template"
+      version = "2.2.0"
+    }
+    null = {
+      source  = "hashicorp/null"
+      version = "3.2.4"
+    }
   }
 }
 
@@ -12,17 +24,88 @@ variable "do_token"{
   type        = string
 }
 
+variable "machines" {
+  type        = list(string)
+  description = "Machine names, corresponding to machine-NAME.yaml.tmpl files"
+}
+
+variable "cluster_name" {
+  type        = string
+  description = "Cluster name used as prefix for the machine names"
+}
+
+variable "ssh_keys" {
+  type        = list(string)
+  description = "SSH public keys for user 'core' (and to register on Digital Ocean for the first)"
+}
+
+variable "server_type" {
+  type        = string
+  default     = "s-1vcpu-1gb"
+  description = "The server type to rent"
+}
+
+variable "datacenter" {
+  type        = string
+  description = "The region to deploy in"
+}
+
+variable "flatcar_stable_version" {
+  type        = string
+  description = "The Flatcar Stable release you want to use for the initial installation, e.g., 2605.12.0"
+}
+
 provider "digitalocean" {
   token = var.do_token
 }
 
-resource "digitalocean_droplet" "web" {
-  image = "ubuntu-25-04-x64"
-  name = "web-1"
-  region = "sfo3"
-  size = "s-1vcpu-1gb"
+resource "digitalocean_ssh_key" "first" {
+  name       = var.cluster_name
+  public_key = var.ssh_keys.0
+}
+
+resource "digitalocean_custom_image" "flatcar" {
+  name    = "flatcar-stable-${var.flatcar_stable_version}"
+  url     = "https://stable.release.flatcar-linux.net/amd64-usr/${var.flatcar_stable_version}/flatcar_production_digitalocean_image.bin.bz2"
+  regions = [var.datacenter]
+}
+
+resource "digitalocean_droplet" "machine" {
+  for_each  = toset(var.machines)
+  name      = "${var.cluster_name}-${each.key}"
+  image     = digitalocean_custom_image.flatcar.id
+  region    = var.datacenter
+  size      = var.server_type
+  ssh_keys  = [digitalocean_ssh_key.first.fingerprint]
+  user_data = data.ct_config.machine-ignitions[each.key].rendered
+  lifecycle {
+    create_before_destroy = true
+  }
+}
+
+data "ct_config" "machine-ignitions" {
+  for_each = toset(var.machines)
+  # content  = data.template_file.machine-configs[each.key].rendered
+  content = templatefile("${path.module}/cl/machine-${each.key}.yaml.tmpl", {
+    ssh_keys = jsonencode(var.ssh_keys),
+    name = each.key
+  })
+  strict = true
 }
 
-output "web_ip" {
-  value = digitalocean_droplet.web.ipv4_address
+#data "template_file" "machine-configs" {
+#  for_each = toset(var.machines)
+#  template = file("${path.module}/cl/machine-${each.key}.yaml.tmpl")
+
+#  vars = {
+#    ssh_keys = jsonencode(var.ssh_keys)
+#    name     = each.key
+#  }
+#}
+
+output "ip-addresses" {
+  value = {
+    for key in var.machines :
+    "${var.cluster_name}-${key}" => digitalocean_droplet.machine[key].ipv4_address
+  }
 }

template.tfvars

@@ -0,0 +1,7 @@
+do_token = "" # token from "API" settings on DigitalOcean
+
+cluster_name           = "mycluster"
+machines               = ["mynode"]
+datacenter             = "sfo3"
+ssh_keys               = [""] # paste contents of id_rsa.pub
+flatcar_stable_version = "4230.2.1"