Compute set of all instance tags in module.design

Use the set of tags in network and aws to avoid creating a
placement group when not required to.

Author: cmd-ntrf

aws/infrastructure.tf

@@ -67,6 +67,7 @@ locals {
 }
 
 resource "aws_placement_group" "efa_group" {
+  count    = contains(module.design.all_instance_tags, "efa") ? 1 : 0
   name     = "${var.cluster_name}-efa-placement_group"
   strategy = "cluster"
 }
@@ -87,7 +88,7 @@ resource "aws_instance" "instances" {
   ami               = lookup(each.value, "image", var.image)
   user_data         = base64gzip(module.configuration.user_data[each.key])
   availability_zone = local.availability_zone
-  placement_group   = contains(each.value.tags, "efa") ? aws_placement_group.efa_group.id : null
+  placement_group   = contains(each.value.tags, "efa") ? aws_placement_group.efa_group[0].id : null
 
   key_name          = aws_key_pair.key.key_name
 

aws/network.tf

@@ -48,8 +48,7 @@ resource "aws_security_group" "allow_out_any" {
 }
 
 locals {
-  all_tags   = toset(flatten([ for key, value in module.design.instances: value.tags ]))
-  sec_groups = toset([ for name, rule in var.firewall_rules: rule.tag if contains(local.all_tags, rule.tag) ])
+  sec_groups = toset([ for name, rule in var.firewall_rules: rule.tag if contains(module.design.all_instance_tags, rule.tag) ])
 }
 
 resource "aws_security_group" "external" {

common/design/outputs.tf

@@ -21,3 +21,7 @@ output "domain_name" {
 output "bastion_tag" {
   value = local.bastion_tag
 }
+
+output "all_instance_tags" {
+  value = toset(flatten([for instance in local.instances: instance.tags]))
+}

gcp/network.tf

@@ -46,12 +46,8 @@ resource "google_compute_firewall" "allow_all_internal" {
 
 }
 
-locals {
-  all_tags = toset(flatten([ for key, value in module.design.instances: value.tags ]))
-}
-
 resource "google_compute_firewall" "default" {
-  for_each = { for name, rule in var.firewall_rules: name => rule if contains(local.all_tags, rule.tag) }
+  for_each = { for name, rule in var.firewall_rules: name => rule if contains(module.design.all_instance_tags, rule.tag) }
   name     = format("%s-%s", var.cluster_name, lower(each.key))
   network  = google_compute_network.network.self_link
 

openstack/network-2.tf

@@ -31,8 +31,7 @@ resource openstack_networking_secgroup_rule_v2 "udp" {
 }
 
 locals {
-  all_tags   = toset(flatten([ for key, value in module.design.instances: value.tags ]))
-  sec_groups = toset([ for name, rule in var.firewall_rules: rule.tag if contains(local.all_tags, rule.tag) ])
+  sec_groups = toset([ for name, rule in var.firewall_rules: rule.tag if contains(module.design.all_instance_tags, rule.tag) ])
 }
 
 resource "openstack_networking_secgroup_v2" "external" {