Add optional support for using existing floating IPs

modules/vshn-lbaas-cloudscale/README.md

@@ -23,6 +23,7 @@ The module provides variables to
 * specify a cloudscale.ch API secret for Floaty
 * specify the username for the APPUiO hieradata Git repository (see next sections for details).
 * provide an API token for control.vshn.net (see next sections for details).
+* use pre-existing cloudscale floating IPs for api, ingress and egress.
 
 ## Required credentials
 

modules/vshn-lbaas-cloudscale/hiera.tf

@@ -17,10 +17,10 @@ module "hiera" {
   ingress_controller    = var.ingress_controller
   lb_names              = random_id.lb[*].hex
   hieradata_repo_user   = var.hieradata_repo_user
-  api_vip               = cidrhost(cloudscale_floating_ip.api_vip[0].network, 0)
+  api_vip               = cidrhost(local.api_vip.network, 0)
   internal_vip          = var.internal_vip
-  nat_vip               = cidrhost(cloudscale_floating_ip.nat_vip[0].network, 0)
-  router_vip            = cidrhost(cloudscale_floating_ip.router_vip[0].network, 0)
+  nat_vip               = cidrhost(local.nat_vip.network, 0)
+  router_vip            = cidrhost(local.router_vip.network, 0)
   team                  = var.team
   enable_proxy_protocol = var.enable_proxy_protocol
 

modules/vshn-lbaas-cloudscale/main.tf

@@ -1,5 +1,5 @@
 resource "cloudscale_floating_ip" "api_vip" {
-  count       = var.lb_count != 0 ? 1 : 0
+  count       = var.lb_count != 0 && !var.use_existing_vips ? 1 : 0
   ip_version  = 4
   region_slug = var.region
   reverse_ptr = "api.${var.node_name_suffix}"
@@ -13,8 +13,14 @@ resource "cloudscale_floating_ip" "api_vip" {
   }
 }
 
+data "cloudscale_floating_ip" "api_vip" {
+  count       = var.use_existing_vips ? 1 : 0
+  ip_version  = 4
+  reverse_ptr = "api.${var.node_name_suffix}"
+}
+
 resource "cloudscale_floating_ip" "router_vip" {
-  count       = var.lb_count != 0 ? 1 : 0
+  count       = var.lb_count != 0 && !var.use_existing_vips ? 1 : 0
   ip_version  = 4
   region_slug = var.region
   reverse_ptr = "ingress.${var.node_name_suffix}"
@@ -28,8 +34,14 @@ resource "cloudscale_floating_ip" "router_vip" {
   }
 }
 
+data "cloudscale_floating_ip" "router_vip" {
+  count       = var.use_existing_vips ? 1 : 0
+  ip_version  = 4
+  reverse_ptr = "ingress.${var.node_name_suffix}"
+}
+
 resource "cloudscale_floating_ip" "nat_vip" {
-  count       = var.lb_count != 0 ? 1 : 0
+  count       = var.lb_count != 0 && !var.use_existing_vips ? 1 : 0
   ip_version  = 4
   region_slug = var.region
   reverse_ptr = "egress.${var.node_name_suffix}"
@@ -43,6 +55,12 @@ resource "cloudscale_floating_ip" "nat_vip" {
   }
 }
 
+data "cloudscale_floating_ip" "nat_vip" {
+  count       = var.use_existing_vips ? 1 : 0
+  ip_version  = 4
+  reverse_ptr = "egress.${var.node_name_suffix}"
+}
+
 resource "random_id" "lb" {
   count       = var.lb_count
   prefix      = "lb-"
@@ -57,6 +75,10 @@ resource "cloudscale_server_group" "lb" {
 }
 
 locals {
+  api_vip    = var.use_existing_vips ? data.cloudscale_floating_ip.api_vip[0] : cloudscale_floating_ip.api_vip[0]
+  router_vip = var.use_existing_vips ? data.cloudscale_floating_ip.router_vip[0] : cloudscale_floating_ip.router_vip[0]
+  nat_vip    = var.use_existing_vips ? data.cloudscale_floating_ip.nat_vip[0] : cloudscale_floating_ip.nat_vip[0]
+
   instance_fqdns = formatlist("%s.${var.node_name_suffix}", random_id.lb[*].hex)
 
   common_user_data = {

modules/vshn-lbaas-cloudscale/outputs.tf

@@ -1,13 +1,13 @@
 output "api_vip" {
-  value = cloudscale_floating_ip.api_vip
+  value = local.api_vip
 }
 
 output "nat_vip" {
-  value = cloudscale_floating_ip.nat_vip
+  value = local.nat_vip
 }
 
 output "router_vip" {
-  value = cloudscale_floating_ip.router_vip
+  value = local.router_vip
 }
 
 output "server_names" {

modules/vshn-lbaas-cloudscale/variables.tf

@@ -106,3 +106,9 @@ variable "enable_proxy_protocol" {
   description = "Enable the PROXY protocol for the Router backends. WARNING: Connections will fail until you enable the same on the OpenShift router as well"
   default     = false
 }
+
+variable "use_existing_vips" {
+  type        = bool
+  description = "Use existing floating IPs for api_vip, router_vip and nat_vip. Manually set the reverse DNS info, so the correct data source is found."
+  default     = false
+}