not hardcode the ip allocation for agents

agents.tf

@@ -12,7 +12,6 @@ module "agents" {
   placement_group_id     = hcloud_placement_group.k3s.id
   location               = var.location
   network_id             = hcloud_network.k3s.id
-  ip                     = cidrhost(hcloud_network_subnet.k3s.ip_range, 513 + each.value.index)
   server_type            = each.value.server_type
 
   labels = {
@@ -45,7 +44,7 @@ resource "null_resource" "agents" {
       token         = random_password.k3s_token.result
       kubelet-arg   = "cloud-provider=external"
       flannel-iface = "eth1"
-      node-ip       = cidrhost(hcloud_network_subnet.k3s.ip_range, 513 + each.value.index)
+      node-ip       = module.agents[each.key].ipv4_address
       node-label    = var.automatically_upgrade_k3s ? ["k3s_upgrade=true"] : []
     })
     destination = "/tmp/config.yaml"

locals.tf

@@ -33,7 +33,7 @@ locals {
 
   agent_nodepools = merge([
     for nodepool_name, nodepool_obj in var.agent_nodepools : {
-      for index in range(nodepool_obj.count) :
+      for index in range(lookup(nodepool_obj, "count", var.agents_num)) :
       format("%s-%s", nodepool_name, index) => {
         index : index, # just for the compatibility with previous structure
         server_type : nodepool_obj.server_type

modules/host/main.tf

@@ -14,7 +14,7 @@ resource "hcloud_server" "server" {
 
   network {
     network_id = var.network_id
-    ip         = var.ip
+    ip         = try(var.ip, null)
   }
 
   connection {

modules/host/variables.tf

@@ -60,6 +60,7 @@ variable "network_id" {
 }
 
 variable "ip" {
+  default     = null
   description = "The IP"
   type        = string
   nullable    = true

variables.tf

@@ -52,12 +52,14 @@ variable "servers_num" {
   type        = number
 }
 
+variable "agents_num" {
+  description = "Default agent server type"
+  type        = number
+}
+
 variable "agent_nodepools" {
   description = "Number of agent nodes."
-  type = map(object({
-    server_type = string
-    count       = number
-  }))
+  type        = map(any)
 }
 
 variable "hetzner_ccm_version" {