Upcloud: Add possibility to setup cluster using nodes with no public IPs (#11696)

* terraform upcloud: Added possibility to set up nodes with only private IPs

* terraform upcloud: add support for gateway in private zone

* terraform upcloud: split LB proxy protocol config per backend

* terraform upcloud: fix flexible plans

* terraform upcloud: Removed overview of cluster setup

---------

Co-authored-by: davidumea <david.andersson@elastisys.com>

contrib/terraform/upcloud/README.md

@@ -2,35 +2,6 @@
 
 Provision a Kubernetes cluster on [UpCloud](https://upcloud.com/) using Terraform and Kubespray
 
-## Overview
-
-The setup looks like following
-
-```text
-   Kubernetes cluster
-+--------------------------+
-|      +--------------+    |
-|      | +--------------+  |
-| -->  | |              |  |
-|      | | Master/etcd  |  |
-|      | | node(s)      |  |
-|      +-+              |  |
-|        +--------------+  |
-|              ^           |
-|              |           |
-|              v           |
-|      +--------------+    |
-|      | +--------------+  |
-| -->  | |              |  |
-|      | |    Worker    |  |
-|      | |    node(s)   |  |
-|      +-+              |  |
-|        +--------------+  |
-+--------------------------+
-```
-
-The nodes uses a private network for node to node communication and a public interface for all external communication.
-
 ## Requirements
 
 * Terraform 0.13.0 or newer
@@ -100,6 +71,8 @@ terraform destroy --var-file cluster-settings.tfvars \
 * `template_name`: The name or UUID  of a base image
 * `username`: a user to access the nodes, defaults to "ubuntu"
 * `private_network_cidr`: CIDR to use for the private network, defaults to "172.16.0.0/24"
+* `dns_servers`: DNS servers that will be used by the nodes. Until [this is solved](https://github.com/UpCloudLtd/terraform-provider-upcloud/issues/562) this is done using user_data to reconfigure resolved. Defaults to `[]`
+* `use_public_ips`: If a NIC connencted to the Public network should be attached to all nodes by default. Can be overridden by `force_public_ip` if this is set to `false`. Defaults to `true`
 * `ssh_public_keys`: List of public SSH keys to install on all machines
 * `zone`: The zone where to run the cluster
 * `machines`: Machines to provision. Key of this object will be used as the name of the machine
@@ -108,6 +81,8 @@ terraform destroy --var-file cluster-settings.tfvars \
   * `cpu`: number of cpu cores
   * `mem`: memory size in MB
   * `disk_size`: The size of the storage in GB
+  * `force_public_ip`: If `use_public_ips` is set to `false`, this forces a public NIC onto the machine anyway when set to `true`. Useful if you're migrating from public nodes to only private. Defaults to `false`
+  * `dns_servers`: This works the same way as the global `dns_severs` but only applies to a single node. If set to `[]` while the global `dns_servers` is set to something else, then it will not add the user_data and thus will not be recreated. Useful if you're migrating from public nodes to only private. Defaults to `null`
   * `additional_disks`: Additional disks to attach to the node.
     * `size`: The size of the additional disk in GB
     * `tier`: The tier of disk to use (`maxiops` is the only one you can choose atm)
@@ -139,6 +114,7 @@ terraform destroy --var-file cluster-settings.tfvars \
   * `port`: Port to load balance.
   * `target_port`: Port to the backend servers.
   * `backend_servers`: List of servers that traffic to the port should be forwarded to.
+  * `proxy_protocol`: If the loadbalancer should set up the backend using proxy protocol.
 * `router_enable`: If a router should be connected to the private network or not
 * `gateways`: Gateways that should be connected to the router, requires router_enable is set to true
   * `features`: List of features for the gateway
@@ -171,3 +147,27 @@ terraform destroy --var-file cluster-settings.tfvars \
 * `server_groups`: Group servers together
   * `servers`: The servers that should be included in the group.
   * `anti_affinity_policy`: Defines if a server group is an anti-affinity group. Setting this to "strict" or yes" will result in all servers in the group being placed on separate compute hosts. The value can be "strict", "yes" or "no". "strict" refers to strict policy doesn't allow servers in the same server group to be on the same host. "yes" refers to best-effort policy and tries to put servers on different hosts, but this is not guaranteed.
+
+## Migration
+
+When `null_resource.inventories` and `data.template_file.inventory` was changed to `local_file.inventory` the old state file needs to be cleaned of the old state.
+The error messages you'll see if you encounter this is:
+
+```text
+Error: failed to read schema for null_resource.inventories in registry.terraform.io/hashicorp/null: failed to instantiate provider "registry.terraform.io/hashicorp/null" to obtain schema: unavailable provider "registry.terraform.io/hashicorp/null"
+Error: failed to read schema for data.template_file.inventory in registry.terraform.io/hashicorp/template: failed to instantiate provider "registry.terraform.io/hashicorp/template" to obtain schema: unavailable provider "registry.terraform.io/hashicorp/template"
+```
+
+This can be fixed with the following lines
+
+```bash
+terraform state rm -state=terraform.tfstate null_resource.inventories
+terraform state rm -state=terraform.tfstate data.template_file.inventory
+```
+
+### Public to Private only migration
+
+Since there's no way to remove the public NIC on a machine without recreating its private NIC it's not possible to inplace change a cluster to only use private IPs.
+The way to migrate is to first set `use_public_ips` to `false`, `dns_servers` to some DNS servers and then update all existing servers to have `force_public_ip` set to `true` and `dns_severs` set to `[]`.
+After that you can add new nodes without `force_public_ip` and `dns_servers` set and create them.
+Add the new nodes into the cluster and when all of them are added, remove the old nodes.

contrib/terraform/upcloud/cluster-settings.tfvars

@@ -124,9 +124,9 @@ worker_allowed_ports = []
 
 loadbalancer_enabled = false
 loadbalancer_plan    = "development"
-loadbalancer_proxy_protocol = false
 loadbalancers = {
   # "http" : {
+  #   "proxy_protocol" : false
   #   "port" : 80,
   #   "target_port" : 80,
   #   "backend_servers" : [

contrib/terraform/upcloud/main.tf

@@ -20,6 +20,8 @@ module "kubernetes" {
   username      = var.username
 
   private_network_cidr = var.private_network_cidr
+  dns_servers          = var.dns_servers
+  use_public_ips       = var.use_public_ips
 
   machines = var.machines
 
@@ -30,12 +32,12 @@ module "kubernetes" {
   firewall_default_deny_out  = var.firewall_default_deny_out
   master_allowed_remote_ips  = var.master_allowed_remote_ips
   k8s_allowed_remote_ips     = var.k8s_allowed_remote_ips
+  bastion_allowed_remote_ips = var.bastion_allowed_remote_ips
   master_allowed_ports       = var.master_allowed_ports
   worker_allowed_ports       = var.worker_allowed_ports
 
   loadbalancer_enabled        = var.loadbalancer_enabled
   loadbalancer_plan           = var.loadbalancer_plan
-  loadbalancer_outbound_proxy_protocol = var.loadbalancer_proxy_protocol ? "v2" : ""
   loadbalancer_legacy_network = var.loadbalancer_legacy_network
   loadbalancers               = var.loadbalancers
 
@@ -52,32 +54,12 @@ module "kubernetes" {
 # Generate ansible inventory
 #
 
-data "template_file" "inventory" {
+resource "local_file" "inventory" {
-  template = file("${path.module}/templates/inventory.tpl")
+  content = templatefile("${path.module}/templates/inventory.tpl", {
-
+    master_ip  = module.kubernetes.master_ip
-  vars = {
+    worker_ip  = module.kubernetes.worker_ip
-    connection_strings_master = join("\n", formatlist("%s ansible_user=ubuntu ansible_host=%s ip=%s etcd_member_name=etcd%d",
+    bastion_ip = module.kubernetes.bastion_ip
-      keys(module.kubernetes.master_ip),
+    username   = var.username
-      values(module.kubernetes.master_ip).*.public_ip,
+  })
-      values(module.kubernetes.master_ip).*.private_ip,
+  filename = var.inventory_file
-    range(1, length(module.kubernetes.master_ip) + 1)))
-    connection_strings_worker = join("\n", formatlist("%s ansible_user=ubuntu ansible_host=%s ip=%s",
-      keys(module.kubernetes.worker_ip),
-      values(module.kubernetes.worker_ip).*.public_ip,
-    values(module.kubernetes.worker_ip).*.private_ip))
-    list_master = join("\n", formatlist("%s",
-    keys(module.kubernetes.master_ip)))
-    list_worker = join("\n", formatlist("%s",
-    keys(module.kubernetes.worker_ip)))
-  }
-}
-
-resource "null_resource" "inventories" {
-  provisioner "local-exec" {
-    command = "echo '${data.template_file.inventory.rendered}' > ${var.inventory_file}"
-  }
-
-  triggers = {
-    template = data.template_file.inventory.rendered
-  }
 }

contrib/terraform/upcloud/modules/kubernetes-cluster/main.tf

@@ -53,6 +53,44 @@ locals {
   # If prefix is set, all resources will be prefixed with "${var.prefix}-"
   # Else don't prefix with anything
   resource-prefix = "%{if var.prefix != ""}${var.prefix}-%{endif}"
+
+  master_ip = {
+    for instance in upcloud_server.master :
+      instance.hostname => {
+        for nic in instance.network_interface :
+          nic.type => nic.ip_address
+        if nic.ip_address != null
+      }
+  }
+  worker_ip = {
+    for instance in upcloud_server.worker :
+      instance.hostname => {
+        for nic in instance.network_interface :
+          nic.type => nic.ip_address
+        if nic.ip_address != null
+      }
+  }
+
+  bastion_ip = {
+    for instance in upcloud_server.bastion :
+      instance.hostname => {
+        for nic in instance.network_interface :
+          nic.type => nic.ip_address
+        if nic.ip_address != null
+      }
+  }
+
+  node_user_data = {
+    for name, machine in var.machines :
+      name => <<EOF
+%{ if ( length(machine.dns_servers != null ? machine.dns_servers : [] ) > 0 ) || ( length(var.dns_servers) > 0 && machine.dns_servers == null ) ~}
+#!/bin/bash
+echo -e "[Resolve]\nDNS=${ join(" ", length(machine.dns_servers != null ? machine.dns_servers : []) > 0 ? machine.dns_servers : var.dns_servers) }" > /etc/systemd/resolved.conf
+
+systemctl restart systemd-resolved
+%{ endif ~}
+EOF
+  }
 }
 
 resource "upcloud_network" "private" {
@@ -62,6 +100,9 @@ resource "upcloud_network" "private" {
   ip_network {
     address            = var.private_network_cidr
     dhcp_default_route = var.router_enable
+    # TODO: When support for dhcp_dns for private networks are in, remove the user_data and enable it here.
+    #       See more here https://github.com/UpCloudLtd/terraform-provider-upcloud/issues/562
+    # dhcp_dns           = length(var.private_network_dns) > 0 ? var.private_network_dns : null
     dhcp               = true
     family             = "IPv4"
   }
@@ -89,8 +130,8 @@ resource "upcloud_server" "master" {
 
   hostname     = "${local.resource-prefix}${each.key}"
   plan         = each.value.plan
-  cpu          = each.value.plan == null ? null : each.value.cpu
+  cpu          = each.value.cpu
-  mem          = each.value.plan == null ? null : each.value.mem
+  mem          = each.value.mem
   zone         = var.zone
   server_group = each.value.server_group == null ? null : upcloud_server_group.server_groups[each.value.server_group].id
 
@@ -99,10 +140,13 @@ resource "upcloud_server" "master" {
     size    = each.value.disk_size
   }
 
-  # Public network interface
+  dynamic "network_interface" {
-  network_interface {
+    for_each = each.value.force_public_ip || var.use_public_ips ? [1] : []
+
+    content {
       type = "public"
     }
+  }
 
   # Private network interface
   network_interface {
@@ -136,6 +180,9 @@ resource "upcloud_server" "master" {
     keys            = var.ssh_public_keys
     create_password = false
   }
+
+  metadata = local.node_user_data[each.key] != "" ? true : null
+  user_data = local.node_user_data[each.key] != "" ? local.node_user_data[each.key] : null
 }
 
 resource "upcloud_server" "worker" {
@@ -147,8 +194,8 @@ resource "upcloud_server" "worker" {
 
   hostname     = "${local.resource-prefix}${each.key}"
   plan         = each.value.plan
-  cpu          = each.value.plan == null ? null : each.value.cpu
+  cpu          = each.value.cpu
-  mem          = each.value.plan == null ? null : each.value.mem
+  mem          = each.value.mem
   zone         = var.zone
   server_group = each.value.server_group == null ? null : upcloud_server_group.server_groups[each.value.server_group].id
 
@@ -158,10 +205,13 @@ resource "upcloud_server" "worker" {
     size    = each.value.disk_size
   }
 
-  # Public network interface
+  dynamic "network_interface" {
-  network_interface {
+    for_each = each.value.force_public_ip || var.use_public_ips ? [1] : []
+
+    content {
       type = "public"
     }
+  }
 
   # Private network interface
   network_interface {
@@ -195,6 +245,63 @@ resource "upcloud_server" "worker" {
     keys            = var.ssh_public_keys
     create_password = false
   }
+
+  metadata = local.node_user_data[each.key] != "" ? true : null
+  user_data = local.node_user_data[each.key] != "" ? local.node_user_data[each.key] : null
+}
+
+resource "upcloud_server" "bastion" {
+  for_each = {
+    for name, machine in var.machines :
+    name => machine
+    if machine.node_type == "bastion"
+  }
+
+  hostname     = "${local.resource-prefix}${each.key}"
+  plan         = each.value.plan
+  cpu          = each.value.cpu
+  mem          = each.value.mem
+  zone         = var.zone
+  server_group = each.value.server_group == null ? null : upcloud_server_group.server_groups[each.value.server_group].id
+
+
+  template {
+    storage = var.template_name
+    size    = each.value.disk_size
+  }
+
+  # Private network interface
+  network_interface {
+    type    = "private"
+    network = upcloud_network.private.id
+  }
+
+  # Private network interface
+  network_interface {
+    type    = "public"
+  }
+
+  firewall = var.firewall_enabled
+
+  dynamic "storage_devices" {
+    for_each = {
+      for disk_key_name, disk in upcloud_storage.additional_disks :
+      disk_key_name => disk
+      # Only add the disk if it matches the node name in the start of its name
+      if length(regexall("^${each.key}_.+", disk_key_name)) > 0
+    }
+
+    content {
+      storage = storage_devices.value.id
+    }
+  }
+
+  # Include at least one public SSH key
+  login {
+    user            = var.username
+    keys            = var.ssh_public_keys
+    create_password = false
+  }
 }
 
 resource "upcloud_firewall_rules" "master" {
@@ -543,6 +650,53 @@ resource "upcloud_firewall_rules" "k8s" {
   }
 }
 
+resource "upcloud_firewall_rules" "bastion" {
+  for_each  = upcloud_server.bastion
+  server_id = each.value.id
+
+  dynamic "firewall_rule" {
+    for_each = var.bastion_allowed_remote_ips
+
+    content {
+      action                 = "accept"
+      comment                = "Allow bastion SSH access from this network"
+      destination_port_end   = "22"
+      destination_port_start = "22"
+      direction              = "in"
+      family                 = "IPv4"
+      protocol               = "tcp"
+      source_address_end     = firewall_rule.value.end_address
+      source_address_start   = firewall_rule.value.start_address
+    }
+  }
+
+  dynamic "firewall_rule" {
+    for_each = length(var.bastion_allowed_remote_ips) > 0 ? [1] : []
+
+    content {
+      action                 = "drop"
+      comment                = "Drop bastion SSH access from other networks"
+      destination_port_end   = "22"
+      destination_port_start = "22"
+      direction              = "in"
+      family                 = "IPv4"
+      protocol               = "tcp"
+      source_address_end     = "255.255.255.255"
+      source_address_start   = "0.0.0.0"
+    }
+  }
+
+  firewall_rule {
+    action    = var.firewall_default_deny_in ? "drop" : "accept"
+    direction = "in"
+  }
+
+  firewall_rule {
+    action    = var.firewall_default_deny_out ? "drop" : "accept"
+    direction = "out"
+  }
+}
+
 resource "upcloud_loadbalancer" "lb" {
   count             = var.loadbalancer_enabled ? 1 : 0
   configured_status = "started"
@@ -583,7 +737,7 @@ resource "upcloud_loadbalancer_backend" "lb_backend" {
   loadbalancer = upcloud_loadbalancer.lb[0].id
   name         = "lb-backend-${each.key}"
   properties {
-    outbound_proxy_protocol = var.loadbalancer_outbound_proxy_protocol
+    outbound_proxy_protocol = each.value.proxy_protocol ? "v2" : ""
   }
 }
 
@@ -622,7 +776,7 @@ resource "upcloud_loadbalancer_static_backend_member" "lb_backend_member" {
 
   backend      = upcloud_loadbalancer_backend.lb_backend[each.value.lb_name].id
   name         = "${local.resource-prefix}${each.key}"
-  ip           = merge(upcloud_server.master, upcloud_server.worker)[each.value.server_name].network_interface[1].ip_address
+  ip           = merge(local.master_ip, local.worker_ip)["${local.resource-prefix}${each.value.server_name}"].private
   port         = each.value.port
   weight       = 100
   max_sessions = var.loadbalancer_plan == "production-small" ? 50000 : 1000
@@ -662,7 +816,7 @@ resource "upcloud_router" "router" {
 resource "upcloud_gateway" "gateway" {
   for_each = var.router_enable ? var.gateways : {}
   name = "${local.resource-prefix}${each.key}-gateway"
-  zone = var.zone
+  zone = var.private_cloud ? var.public_zone : var.zone
 
   features = each.value.features
   plan = each.value.plan

contrib/terraform/upcloud/modules/kubernetes-cluster/output.tf

@@ -1,22 +1,13 @@
-
 output "master_ip" {
-  value = {
+  value = local.master_ip
-    for instance in upcloud_server.master :
-    instance.hostname => {
-      "public_ip" : instance.network_interface[0].ip_address
-      "private_ip" : instance.network_interface[1].ip_address
-    }
-  }
 }
 
 output "worker_ip" {
-  value = {
+  value = local.worker_ip
-    for instance in upcloud_server.worker :
-    instance.hostname => {
-      "public_ip" : instance.network_interface[0].ip_address
-      "private_ip" : instance.network_interface[1].ip_address
-    }
 }
+
+output "bastion_ip" {
+  value = local.bastion_ip
 }
 
 output "loadbalancer_domain" {

contrib/terraform/upcloud/modules/kubernetes-cluster/variables.tf

@@ -20,15 +20,21 @@ variable "username" {}
 
 variable "private_network_cidr" {}
 
+variable "dns_servers" {}
+
+variable "use_public_ips" {}
+
 variable "machines" {
   description = "Cluster machines"
   type = map(object({
     node_type = string
     plan      = string
-    cpu       = string
+    cpu       = optional(number)
-    mem       = string
+    mem       = optional(number)
     disk_size = number
     server_group : string
+    force_public_ip : optional(bool, false)
+    dns_servers : optional(set(string))
     additional_disks = map(object({
       size = number
       tier = string
@@ -58,6 +64,13 @@ variable "k8s_allowed_remote_ips" {
   }))
 }
 
+variable "bastion_allowed_remote_ips" {
+  type = list(object({
+    start_address = string
+    end_address   = string
+  }))
+}
+
 variable "master_allowed_ports" {
   type = list(object({
     protocol       = string
@@ -94,10 +107,6 @@ variable "loadbalancer_plan" {
   type = string
 }
 
-variable "loadbalancer_outbound_proxy_protocol" {
-  type = string
-}
-
 variable "loadbalancer_legacy_network" {
   type = bool
   default = false
@@ -107,6 +116,7 @@ variable "loadbalancers" {
   description = "Load balancers"
 
   type = map(object({
+    proxy_protocol          = bool
     port                    = number
     target_port             = number
     allow_internal_frontend = optional(bool)

contrib/terraform/upcloud/output.tf

@@ -7,6 +7,10 @@ output "worker_ip" {
   value = module.kubernetes.worker_ip
 }
 
+output "bastion_ip" {
+  value = module.kubernetes.bastion_ip
+}
+
 output "loadbalancer_domain" {
   value = module.kubernetes.loadbalancer_domain
 }

contrib/terraform/upcloud/templates/inventory.tpl

@@ -1,17 +1,33 @@
-
 [all]
-${connection_strings_master}
+%{ for name, ips in master_ip ~}
-${connection_strings_worker}
+${name} ansible_user=${username} ansible_host=${lookup(ips, "public", ips.private)} ip=${ips.private}
+%{ endfor ~}
+%{ for name, ips in worker_ip ~}
+${name} ansible_user=${username} ansible_host=${lookup(ips, "public", ips.private)} ip=${ips.private}
+%{ endfor ~}
 
 [kube_control_plane]
-${list_master}
+%{ for name, ips in master_ip ~}
+${name}
+%{ endfor ~}
 
 [etcd]
-${list_master}
+%{ for name, ips in master_ip ~}
+${name}
+%{ endfor ~}
 
 [kube_node]
-${list_worker}
+%{ for name, ips in worker_ip ~}
+${name}
+%{ endfor ~}
 
 [k8s_cluster:children]
 kube_control_plane
 kube_node
+
+%{ if length(bastion_ip) > 0 ~}
+[bastion]
+%{ for name, ips in bastion_ip ~}
+bastion ansible_user=${username} ansible_host=${ips.public}
+%{ endfor ~}
+%{ endif ~}

contrib/terraform/upcloud/variables.tf

@@ -32,16 +32,31 @@ variable "private_network_cidr" {
   default     = "172.16.0.0/24"
 }
 
+variable "dns_servers" {
+  description = "DNS servers that will be used by the nodes. Until [this is solved](https://github.com/UpCloudLtd/terraform-provider-upcloud/issues/562) this is done using user_data to reconfigure resolved"
+
+  type    = set(string)
+  default = []
+}
+
+variable "use_public_ips" {
+  description = "If all nodes should get a public IP"
+  type        = bool
+  default     = true
+}
+
 variable "machines" {
   description = "Cluster machines"
 
   type = map(object({
     node_type = string
     plan      = string
-    cpu       = string
+    cpu       = optional(number)
-    mem       = string
+    mem       = optional(number)
     disk_size = number
     server_group : string
+    force_public_ip : optional(bool, false)
+    dns_servers : optional(set(string))
     additional_disks = map(object({
       size = number
       tier = string
@@ -89,6 +104,15 @@ variable "k8s_allowed_remote_ips" {
   default = []
 }
 
+variable "bastion_allowed_remote_ips" {
+  description = "List of IP start/end addresses allowed to SSH to bastion"
+  type = list(object({
+    start_address = string
+    end_address   = string
+  }))
+  default = []
+}
+
 variable "master_allowed_ports" {
   description = "List of ports to allow on masters"
   type = list(object({
@@ -131,11 +155,6 @@ variable "loadbalancer_plan" {
   default     = "development"
 }
 
-variable "loadbalancer_proxy_protocol" {
-  type    = bool
-  default = false
-}
-
 variable "loadbalancer_legacy_network" {
   description = "If the loadbalancer should use the deprecated network field instead of networks blocks. You probably want to have this set to false"
 
@@ -147,6 +166,7 @@ variable "loadbalancers" {
   description = "Load balancers"
 
   type = map(object({
+    proxy_protocol          = bool
     port                    = number
     target_port             = number
     allow_internal_frontend = optional(bool, false)