add specific subnet for nodepool

agents.tf

@@ -11,15 +11,19 @@ module "agents" {
   firewall_ids           = [hcloud_firewall.k3s.id]
   placement_group_id     = hcloud_placement_group.k3s.id
   location               = var.location
-  network_id             = hcloud_network.k3s.id
   server_type            = each.value.server_type
-
+  subnet_id              = hcloud_network_subnet.subnet[each.value.subnet].id
+  private_ip             = cidrhost(var.network_subnets[each.value.subnet], each.value.index + 1)
   labels = {
     "provisioner" = "terraform",
     "engine"      = "k3s"
   }
 
   hcloud_token = var.hcloud_token
+
+  depends_on = [
+    hcloud_network_subnet.subnet
+  ]
 }
 
 resource "null_resource" "agents" {
@@ -73,6 +77,6 @@ resource "null_resource" "agents" {
 
   depends_on = [
     null_resource.first_control_plane,
-    hcloud_network_subnet.k3s
+    hcloud_network_subnet.subnet
   ]
 }

init.tf

@@ -58,7 +58,7 @@ resource "null_resource" "first_control_plane" {
   }
 
   depends_on = [
-    hcloud_network_subnet.k3s
+    hcloud_network_subnet.subnet["control_plane"]
   ]
 }
 

locals.tf

@@ -33,9 +33,11 @@ locals {
 
   agent_nodepools = merge([
     for nodepool_name, nodepool_obj in var.agent_nodepools : {
-      for index in range(lookup(nodepool_obj, "count", var.agents_num)) :
+      for index in range(nodepool_obj.count) :
       format("%s-%s", nodepool_name, index) => {
-        server_type : nodepool_obj.server_type
+        server_type : nodepool_obj.server_type,
+        subnet : lookup(nodepool_obj, "subnet", "default"),
+        index : index
       }
     }
   ]...)

main.tf

@@ -10,14 +10,15 @@ resource "hcloud_ssh_key" "k3s" {
 
 resource "hcloud_network" "k3s" {
   name     = "k3s"
-  ip_range = "10.0.0.0/8"
+  ip_range = var.network_ip_range
 }
 
-resource "hcloud_network_subnet" "k3s" {
+resource "hcloud_network_subnet" "subnet" {
+  for_each     = var.network_subnets
   network_id   = hcloud_network.k3s.id
   type         = "cloud"
   network_zone = var.network_region
-  ip_range     = "10.0.0.0/16"
+  ip_range     = each.value
 }
 
 resource "hcloud_firewall" "k3s" {
@@ -29,8 +30,8 @@ resource "hcloud_firewall" "k3s" {
     protocol  = "tcp"
     port      = "any"
     source_ips = [
+      var.network_ip_range,
       "127.0.0.1/32",
-      "10.0.0.0/8",
       "169.254.169.254/32",
       "213.239.246.1/32"
     ]
@@ -40,8 +41,8 @@ resource "hcloud_firewall" "k3s" {
     protocol  = "udp"
     port      = "any"
     source_ips = [
+      var.network_ip_range,
       "127.0.0.1/32",
-      "10.0.0.0/8",
       "169.254.169.254/32",
       "213.239.246.1/32"
     ]
@@ -50,8 +51,8 @@ resource "hcloud_firewall" "k3s" {
     direction = "in"
     protocol  = "icmp"
     source_ips = [
+      var.network_ip_range,
       "127.0.0.1/32",
-      "10.0.0.0/8",
       "169.254.169.254/32",
       "213.239.246.1/32"
     ]

modules/host/main.tf

@@ -65,6 +65,7 @@ resource "hcloud_server" "server" {
 }
 
 resource "hcloud_server_network" "server" {
+  ip        = var.private_ip
   server_id = hcloud_server.server.id
-  network_id = var.network_id
+  subnet_id = var.subnet_id
 }

modules/host/variables.tf

@@ -54,9 +54,14 @@ variable "location" {
   type        = string
 }
 
-variable "network_id" {
+variable "subnet_id" {
-  description = "The network or subnet id"
+  description = "The subnet id"
-  type        = number
+  type        = string
+}
+
+variable "private_ip" {
+  description = "Private IP for the server"
+  type        = string
 }
 
 variable "server_type" {

servers.tf

@@ -11,8 +11,9 @@ module "control_planes" {
   firewall_ids           = [hcloud_firewall.k3s.id]
   placement_group_id     = hcloud_placement_group.k3s.id
   location               = var.location
-  network_id             = hcloud_network.k3s.id
   server_type            = var.control_plane_server_type
+  subnet_id              = hcloud_network_subnet.subnet["control_plane"].id
+  private_ip             = cidrhost(var.network_subnets["control_plane"], count.index + 1)
 
   labels = {
     "provisioner" = "terraform",
@@ -20,6 +21,10 @@ module "control_planes" {
   }
 
   hcloud_token = var.hcloud_token
+
+  depends_on = [
+    hcloud_network_subnet.subnet
+  ]
 }
 
 resource "null_resource" "control_planes" {
@@ -78,6 +83,6 @@ resource "null_resource" "control_planes" {
 
   depends_on = [
     null_resource.first_control_plane,
-    hcloud_network_subnet.k3s
+    hcloud_network_subnet.subnet
   ]
 }

terraform.tfvars.example

@@ -9,22 +9,30 @@ private_key  = "/home/username/.ssh/id_ed25519"
 # For Hetzner server types see https://www.hetzner.com/cloud
 location         = "fsn1"       # change to `ash` for us-east Ashburn, Virginia location
 network_region   = "eu-central" # change to `us-east` if location is ash
+network_ip_range = "10.0.0.0/8"
+network_subnets = {
+  control_plane = "10.1.0.0/16"
+  subnet1       = "10.2.0.0/16"
+  subnet2       = "10.3.0.0/16"
+}
+
 control_plane_server_type = "cpx11"
 lb_server_type            = "lb11"
 
 # At least 3 server nodes is recommended for HA, otherwise you need to turn off automatic upgrade (see ReadMe).
 servers_num = 3
 
-# For agent nodes, at least 2 is recommended for HA, but you can keep automatic upgrades.
-agents_num                = 2
 
 agent_nodepools = {
   big = {
     server_type = "cpx31",
-    count       = 1
+    count       = 1,
+    subnet      = "subnet1",
   }
   small = {
     server_type = "cpx21",
+    count       = 2,
+    subnet      = "subnet2",
   }
 }
 

variables.tf

@@ -30,6 +30,16 @@ variable "network_region" {
   type        = string
 }
 
+variable "network_ip_range" {
+  description = "Default IP range for network"
+  type        = string
+}
+
+variable "network_subnets" {
+  description = "Subnets definition for default network"
+  type        = map(string)
+}
+
 variable "control_plane_server_type" {
   description = "Default control plane server type"
   type        = string
@@ -52,11 +62,6 @@ variable "servers_num" {
   type        = number
 }
 
-variable "agents_num" {
-  description = "Number of agent nodes."
-  type        = number
-}
-
 variable "agent_nodepools" {
   description = "Number of agent nodes."
   type        = map(any)