fix: Use eu-central network zone, handle existing SSH key

terraform/ssh.tf

@@ -2,7 +2,21 @@ data "local_file" "ssh_public_key" {
   filename = pathexpand(var.ssh_public_key)
 }
 
+data "hcloud_ssh_keys" "all_keys" {}
+
+locals {
+  existing_key = try([
+    for key in data.hcloud_ssh_keys.all_keys.ssh_keys :
+    key if key.name == "${var.cluster_name}-ssh-key"
+  ][0], null)
+}
+
 resource "hcloud_ssh_key" "cluster" {
+  count      = local.existing_key == null ? 1 : 0
   name       = "${var.cluster_name}-ssh-key"
   public_key = data.local_file.ssh_public_key.content
 }
+
+data "hcloud_ssh_key" "cluster" {
+  fingerprint = local.existing_key != null ? local.existing_key.fingerprint : hcloud_ssh_key.cluster[0].fingerprint
+}