[WIP] nodepools feature

agents.tf

@@ -1,9 +1,9 @@
 module "agents" {
   source = "./modules/host"
 
-  count = var.agents_num
-  name  = "k3s-agent-${count.index}"
+  for_each = local.agent_nodepools
 
+  name                   = each.key
   ssh_keys               = [hcloud_ssh_key.k3s.id]
   public_key             = var.public_key
   private_key            = var.private_key
@@ -12,8 +12,8 @@ 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 + count.index)
-  server_type            = var.agent_server_type
+  ip                     = cidrhost(hcloud_network_subnet.k3s.ip_range, 513 + each.value.index)
+  server_type            = each.value.server_type
 
   labels = {
     "provisioner" = "terraform",
@@ -24,28 +24,28 @@ module "agents" {
 }
 
 resource "null_resource" "agents" {
-  count = var.agents_num
+  for_each = local.agent_nodepools
 
   triggers = {
-    agent_id = module.agents[count.index].id
+    agent_id = module.agents[each.key].id
   }
 
   connection {
     user           = "root"
     private_key    = local.ssh_private_key
     agent_identity = local.ssh_identity
-    host           = module.agents[count.index].ipv4_address
+    host           = module.agents[each.key].ipv4_address
   }
 
   # Generating k3s agent config file
   provisioner "file" {
     content = yamlencode({
-      node-name     = module.agents[count.index].name
+      node-name     = module.agents[each.key].name
       server        = "https://${local.first_control_plane_network_ip}:6443"
       token         = random_password.k3s_token.result
       kubelet-arg   = "cloud-provider=external"
       flannel-iface = "eth1"
-      node-ip       = cidrhost(hcloud_network_subnet.k3s.ip_range, 513 + count.index)
+      node-ip       = cidrhost(hcloud_network_subnet.k3s.ip_range, 513 + each.value.index)
       node-label    = var.automatically_upgrade_k3s ? ["k3s_upgrade=true"] : []
     })
     destination = "/tmp/config.yaml"

locals.tf

@@ -30,4 +30,14 @@ locals {
   install_k3s_server = concat(local.common_commands_install_k3s, ["curl -sfL https://get.k3s.io | INSTALL_K3S_SKIP_SELINUX_RPM=true INSTALL_K3S_SKIP_START=true INSTALL_K3S_EXEC=server sh -"])
 
   install_k3s_agent = concat(local.common_commands_install_k3s, ["curl -sfL https://get.k3s.io | INSTALL_K3S_SKIP_SELINUX_RPM=true INSTALL_K3S_SKIP_START=true INSTALL_K3S_EXEC=agent sh -"])
+
+  agent_nodepools = merge([
+    for nodepool_name, nodepool_obj in var.agent_nodepools : {
+      for index in range(nodepool_obj.count) :
+      format("%s-%s", nodepool_name, index) => {
+        index : index, # just for the compatibility with previous structure
+        server_type : nodepool_obj.server_type
+      }
+    }
+  ]...)
 }

output.tf

@@ -4,7 +4,9 @@ output "controlplanes_public_ip" {
 }
 
 output "agents_public_ip" {
-  value       = module.agents.*.ipv4_address
+  value = [
+    for obj in module.agents : obj.ipv4_address
+  ]
   description = "The public IP addresses of the agent server."
 }
 

terraform.tfvars.example

@@ -9,7 +9,6 @@ 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
-agent_server_type         = "cpx21"
 control_plane_server_type = "cpx11"
 lb_server_type            = "lb11"
 
@@ -17,7 +16,17 @@ lb_server_type            = "lb11"
 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       = 3
+  }
+  # Will fail because of the ip address collision (we use index number)
+  # small = {
+  #   server_type = "cpx31",
+  #   count       = 3
+  # }
+}
 
 # If you want to use a specific Hetzner CCM and CSI version, set them below, otherwise leave as is for the latest versions
 # hetzner_ccm_version = ""

variables.tf

@@ -35,10 +35,6 @@ variable "control_plane_server_type" {
   type        = string
 }
 
-variable "agent_server_type" {
-  description = "Default agent server type"
-  type        = string
-}
 
 variable "lb_server_type" {
   description = "Default load balancer server type"
@@ -56,9 +52,12 @@ variable "servers_num" {
   type        = number
 }
 
-variable "agents_num" {
+variable "agent_nodepools" {
   description = "Number of agent nodes."
-  type        = number
+  type = map(object({
+    server_type = string
+    count       = number
+  }))
 }
 
 variable "hetzner_ccm_version" {