allow pre-existing floating IPs to be specified with k8s_master_fips

contrib/terraform/openstack/README.md

@@ -239,6 +239,7 @@ For your cluster, edit `inventory/$CLUSTER/cluster.tfvars`.
 |`network_dns_domain` | (Optional) The dns_domain for the internal network that will be generated |
 |`dns_nameservers`| An array of DNS name server names to be used by hosts in the internal subnet. |
 |`floatingip_pool` | Name of the pool from which floating IPs will be allocated |
+|`k8s_master_fips` | A list of floating IPs that you have already pre-allocated; they will be attached to master nodes instead of creating new random floating IPs. |
 |`external_net` | UUID of the external network that will be routed to |
 |`flavor_k8s_master`,`flavor_k8s_node`,`flavor_etcd`, `flavor_bastion`,`flavor_gfs_node` | Flavor depends on your openstack installation, you can get available flavor IDs through `openstack flavor list` |
 |`image`,`image_gfs` | Name of the image to use in provisioning the compute resources. Should already be loaded into glance. |

contrib/terraform/openstack/kubespray.tf

@@ -27,6 +27,7 @@ module "ips" {
   network_name                  = var.network_name
   router_id                     = module.network.router_id
   k8s_nodes                     = var.k8s_nodes
+  k8s_master_fips               = var.k8s_master_fips
 }
 
 module "compute" {

contrib/terraform/openstack/modules/ips/main.tf

@@ -4,14 +4,16 @@ resource "null_resource" "dummy_dependency" {
   }
 }
 
+# If user specifies pre-existing IPs to use in k8s_master_fips, do not create new ones.
 resource "openstack_networking_floatingip_v2" "k8s_master" {
-  count      = var.number_of_k8s_masters
+  count      = length(var.k8s_master_fips) > 0 ? 0 : var.number_of_k8s_masters
   pool       = var.floatingip_pool
   depends_on = [null_resource.dummy_dependency]
 }
 
+# If user specifies pre-existing IPs to use in k8s_master_fips, do not create new ones.
 resource "openstack_networking_floatingip_v2" "k8s_master_no_etcd" {
-  count      = var.number_of_k8s_masters_no_etcd
+  count      = length(var.k8s_master_fips) > 0 ? 0 : var.number_of_k8s_masters_no_etcd
   pool       = var.floatingip_pool
   depends_on = [null_resource.dummy_dependency]
 }

contrib/terraform/openstack/modules/ips/outputs.tf

@@ -1,9 +1,11 @@
+# If k8s_master_fips is already defined as input, keep the same value since new FIPs have not been created.
 output "k8s_master_fips" {
-  value = openstack_networking_floatingip_v2.k8s_master[*].address
+  value = length(var.k8s_master_fips) > 0 ? var.k8s_master_fips : openstack_networking_floatingip_v2.k8s_master[*].address
 }
 
+# If k8s_master_fips is already defined as input, keep the same value since new FIPs have not been created.
 output "k8s_master_no_etcd_fips" {
-  value = openstack_networking_floatingip_v2.k8s_master_no_etcd[*].address
+  value = length(var.k8s_master_fips) > 0 ? var.k8s_master_fips : openstack_networking_floatingip_v2.k8s_master_no_etcd[*].address
 }
 
 output "k8s_node_fips" {

contrib/terraform/openstack/modules/ips/variables.tf

@@ -17,3 +17,5 @@ variable "router_id" {
 }
 
 variable "k8s_nodes" {}
+
+variable "k8s_master_fips" {}

contrib/terraform/openstack/variables.tf

@@ -156,6 +156,12 @@ variable "dns_nameservers" {
   default     = []
 }
 
+variable "k8s_master_fips" {
+  description = "specific pre-existing floating IPs to use for master nodes"
+  type        = list(string)
+  default     = []
+}
+
 variable "floatingip_pool" {
   description = "name of the floating ip pool to use"
   default     = "external"