fix: Open port 2377 only on manager nodes

terraform/modules/docker-network/swarm-node.tf

@@ -78,6 +78,7 @@ resource "hcloud_server" "node" {
     packages_setup : base64encode(file("${path.module}/templates/scripts/install-packages.sh"))
     firewall_setup : base64encode(templatefile("${path.module}/templates/scripts/firewall-setup.sh.tftpl", {
       node_ip : var.private_node_ips[count.index]
+      main_node : count.index == 0
     }))
     ssh_setup : base64encode(templatefile("${path.module}/templates/scripts/ssh-setup.sh.tftpl", {
       admin_user : var.admin_user

terraform/modules/docker-network/templates/scripts/firewall-setup.sh.tftpl

@@ -7,7 +7,9 @@ ufw allow OpenSSH
 ufw allow 80 comment HTTP
 ufw allow 443 comment HTTPS
 
-ufw allow to ${node_ip} port 2377 comment "Swarm join port"
+%{if main_node ~}
+ufw allow to ${node_ip} port 2377 comment "Swarm join port and communication between manager nodes"
+%{endif ~}
 ufw allow to ${node_ip} port 7946 comment "overlay network node discovery"
 ufw allow to ${node_ip} port 4789 comment "overlay network traffic"
 ufw enable