feat: add flatcar image

Signed-off-by: Vojtěch Mareš <vojtech@mares.cz>

images/flatcar/image.pkr.hcl

@@ -0,0 +1,60 @@
+packer {
+  required_plugins {
+    hcloud = {
+      source  = "github.com/hetznercloud/hcloud"
+      version = "~> 1.4.0"
+    }
+  }
+}
+
+variable "channel" {
+  type    = string
+  default = "stable"
+}
+
+variable "hcloud_token" {
+  type      = string
+  default   = env("HCLOUD_TOKEN")
+  sensitive = true
+}
+
+source "hcloud" "flatcar" {
+  token = var.hcloud_token
+
+  image    = "ubuntu-24.04"
+  location = "fsn1"
+  rescue   = "linux64"
+
+  snapshot_labels = {
+    os      = "flatcar"
+    channel = var.channel
+  }
+
+  ssh_username = "root"
+}
+
+build {
+  source "hcloud.flatcar" {
+    name          = "x86"
+    server_type   = "cx22"
+    snapshot_name = "flatcar-${var.channel}-amd64"
+  }
+
+  source "hcloud.flatcar" {
+    name          = "arm"
+    server_type   = "cax11"
+    snapshot_name = "flatcar-${var.channel}-arm64"
+  }
+
+  provisioner "shell" {
+    inline = [
+      # Download script and dependencies
+      "apt-get -y install gawk",
+      "curl -fsSLO --retry-delay 1 --retry 60 --retry-connrefused --retry-max-time 60 --connect-timeout 20 https://raw.githubusercontent.com/flatcar/init/flatcar-master/bin/flatcar-install",
+      "chmod +x flatcar-install",
+
+      # Install flatcar
+      "./flatcar-install -s -o hetzner -C ${var.channel}",
+    ]
+  }
+}