From c3e060e92704008b26c19f9420c61f1b24285fbd Mon Sep 17 00:00:00 2001
From: Lei Li <cdlleili@cn.ibm.com>
Date: Tue, 21 Nov 2023 00:17:48 -0800
Subject: [PATCH] terraform: add existing VPC and subnet

Enable the creation of VSIs in existing
VPC and subnet

Signed-off-by: Lei Li <genjuro214@gmail.com>
Signed-off-by: Lei Li <cdlleili@cn.ibm.com>
---
 ibmcloud/cluster/README.md    |  2 ++
 ibmcloud/cluster/main.tf      | 26 ++++++++++++++++++++++----
 ibmcloud/cluster/outputs.tf   |  6 +++---
 ibmcloud/cluster/variables.tf | 12 ++++++++++++
 4 files changed, 39 insertions(+), 7 deletions(-)

diff --git a/ibmcloud/cluster/README.md b/ibmcloud/cluster/README.md
index 811952522..4972b5b54 100644
--- a/ibmcloud/cluster/README.md
+++ b/ibmcloud/cluster/README.md
@@ -86,6 +86,8 @@ Kubernetes node virtual server instances, the VPC and the subnet. If not set it
 defaults to `jp-tok`.
 > - `zone_name` (optional) is the zone in the region Terraform will create the demo environment in. If not set it
 defaults to `jp-tok-2`.
+> - `vpc_name` (optional) is an existing VPC name. If it is not set, Terraform will create a new VPC named "${cluster_name}-vpc".
+> - `subnet_name` (optional) is an existing subnet name. If it is not set, Terraform will create a new subnet named "{cluster_name}-subnet". This must be provided if `vpc_name` has been set.
 > - `ssh_pub_key` (optional) is an variable for a SSH public key which has **not** been registered in IBM Cloud in the
 targeted region. Terraform will manage this key instead. You cannot register the same SSH public key in the same region
 twice under different SSHs key names. This key needs to be password-less and on the 'developer machine' running the terraform in order to perform the cluster set up.
diff --git a/ibmcloud/cluster/main.tf b/ibmcloud/cluster/main.tf
index da2a7ad36..a0ccac80b 100644
--- a/ibmcloud/cluster/main.tf
+++ b/ibmcloud/cluster/main.tf
@@ -3,12 +3,30 @@
 # SPDX-License-Identifier: Apache-2.0
 #
 
+data "ibm_is_vpc" "vpc" {
+  count = var.vpc_name == "" ? 0 : 1
+  name  = var.vpc_name
+}
+
+data "ibm_is_subnet" "subnet" {
+  count = var.subnet_name == "" ? 0 : 1
+  name  = var.subnet_name
+}
+
 module "vpc" {
+  # Create new vpc ans subnet only if vpc_name is not set
+  count        = var.vpc_name == "" ? 1 : 0
   source       = "./vpc"
   cluster_name = var.cluster_name
   zone         = var.zone
 }
 
+locals {
+  vpc_id            = var.vpc_name == "" ? module.vpc[0].vpc_id : data.ibm_is_vpc.vpc[0].id
+  subnet_id         = var.vpc_name == "" ? module.vpc[0].subnet_id : data.ibm_is_subnet.subnet[0].id
+  security_group_id = var.vpc_name == "" ? module.vpc[0].security_group_id : data.ibm_is_vpc.vpc[0].default_security_group
+}
+
 data "ibm_resource_group" "default_group" {
   is_default = "true"
 }
@@ -35,13 +53,13 @@ resource "ibm_is_instance_template" "node_template" {
   name    = "${var.cluster_name}-node-template"
   image   = data.ibm_is_image.node_image.id
   profile = var.node_profile
-  vpc     = module.vpc.vpc_id
+  vpc     = local.vpc_id
   zone    = var.zone
   keys    = [data.ibm_is_ssh_key.ssh_key.id]
 
   primary_network_interface {
-    subnet          = module.vpc.subnet_id
-    security_groups = [module.vpc.security_group_id]
+    subnet          = local.subnet_id
+    security_groups = [local.security_group_id]
   }
 }
 
@@ -86,6 +104,6 @@ resource "null_resource" "label_nodes" {
     null_resource.kubeadm
   ]
   provisioner "local-exec" {
-    command = "./label-nodes.sh ${var.region} ${var.zone} ${module.vpc.subnet_id}"
+    command = "./label-nodes.sh ${var.region} ${var.zone} ${local.subnet_id}"
   }
 }
diff --git a/ibmcloud/cluster/outputs.tf b/ibmcloud/cluster/outputs.tf
index e109e7427..534c4a8be 100644
--- a/ibmcloud/cluster/outputs.tf
+++ b/ibmcloud/cluster/outputs.tf
@@ -1,8 +1,8 @@
-output "vpc_id" { value = module.vpc.vpc_id }
+output "vpc_id" { value = local.vpc_id }
 output "ssh_key_id" { value = data.ibm_is_ssh_key.ssh_key.id }
-output "subnet_id" { value = module.vpc.subnet_id }
+output "subnet_id" { value = local.subnet_id }
 output "node_name" { value = "${var.cluster_name}-node-${length(module.nodes) - 1}" }
-output "security_group_id" { value = module.vpc.security_group_id }
+output "security_group_id" { value = local.security_group_id }
 output "region" { value = var.region }
 output "zone" { value = var.zone }
 output "resource_group_id" { value = data.ibm_resource_group.default_group.id }
diff --git a/ibmcloud/cluster/variables.tf b/ibmcloud/cluster/variables.tf
index 9a839a069..e2308040a 100644
--- a/ibmcloud/cluster/variables.tf
+++ b/ibmcloud/cluster/variables.tf
@@ -17,6 +17,18 @@ variable "ssh_pub_key" {
   default = ""
 }
 
+variable "vpc_name" {
+  type        = string
+  description = "(optional) Specify existing VPC name. If none is provided, it will create a new VPC named {cluster_name}-vpc"
+  default     = ""
+}
+
+variable "subnet_name" {
+  type        = string
+  description = "(optional) Specify existing subnet name. If none is provided, it will create a new subnet named {cluster_name}-subnet. This must be provided if vpc_name has been set"
+  default     = ""
+}
+
 # amd64: ibm-ubuntu-20-04-3-minimal-amd64-1
 # s390x: ibm-ubuntu-20-04-2-minimal-s390x-1
 variable "node_image" {