feat: allow defining custom subnet ip ranges for static agent pools

kube.tf.example

@@ -75,6 +75,7 @@ module "kube-hetzner" {
 
   # Using the default configuration you can only create a maximum of 42 agent-nodepools.
   # This is due to the creation of a subnet for each nodepool with CIDRs being in the shape of 10.[nodepool-index].0.0/16 which collides with k3s' cluster and service IP ranges (defaults below).
+  # To create additional ones (or if you want to use different ranges for other reasons), set the `subnet_ip_range` explicitly for a node pool.
   # Furthermore the maximum number of nodepools (controlplane and agent) is 50, due to a hard limit of 50 subnets per network, see https://docs.hetzner.com/cloud/networks/faq/.
   # So to be able to create a maximum of 50 nodepools in total, the values below have to be changed to something outside that range, e.g. `10.200.0.0/16` and `10.201.0.0/16` for cluster and service respectively.
 
@@ -187,12 +188,13 @@ module "kube-hetzner" {
 
   agent_nodepools = [
     {
-      name        = "agent-small",
-      server_type = "cx22",
-      location    = "fsn1",
-      labels      = [],
-      taints      = [],
-      count       = 1
+      name            = "agent-small",
+      server_type     = "cx22",
+      location        = "fsn1",
+      labels          = [],
+      taints          = [],
+      count           = 1
+      subnet_ip_range = "10.0.0.0/16"
       # swap_size   = "2G" # remember to add the suffix, examples: 512M, 1G
       # zram_size   = "2G" # remember to add the suffix, examples: 512M, 1G
       # kubelet_args = ["kube-reserved=cpu=50m,memory=300Mi,ephemeral-storage=1Gi", "system-reserved=cpu=250m,memory=300Mi"]
@@ -210,6 +212,7 @@ module "kube-hetzner" {
       labels      = [],
       taints      = [],
       count       = 1
+      subnet_ip_range = "10.100.0.0/16"
 
       # Fine-grained control over placement groups (nodes in the same group are spread over different physical servers, 10 nodes per placement group max):
       # placement_group = "default"
@@ -340,7 +343,7 @@ module "kube-hetzner" {
   # easier, as all public traffic passes through a single strongly secured node. It does
   # however also introduce a single point of failure, so if you need high-availability on your
   # egress, you should consider other configurations.
-  # 
+  #
   #
   # nat_router = {
   #   server_type = "cax21"

main.tf

@@ -50,7 +50,7 @@ resource "hcloud_network_subnet" "agent" {
   network_id   = data.hcloud_network.k3s.id
   type         = "cloud"
   network_zone = var.network_region
-  ip_range     = local.network_ipv4_subnets[count.index]
+  ip_range     = coalesce(var.agent_nodepools[count.index].subnet_ip_range, local.network_ipv4_subnets[count.index])
 }
 
 # Subnet for NAT router and other peripherals
@@ -79,4 +79,3 @@ resource "hcloud_firewall" "k3s" {
     }
   }
 }
-

variables.tf

@@ -248,6 +248,7 @@ variable "agent_nodepools" {
     selinux                    = optional(bool, true)
     placement_group_compat_idx = optional(number, 0)
     placement_group            = optional(string, null)
+    subnet_ip_range            = optional(string, null)
     count                      = optional(number, null)
     disable_ipv4               = optional(bool, false)
     disable_ipv6               = optional(bool, false)