From 73c63c8ea47620b65dec5e80426fd5b437e6a262 Mon Sep 17 00:00:00 2001
From: Jamil <jamilbk@users.noreply.github.com>
Date: Wed, 19 Mar 2025 12:28:08 -0700
Subject: [PATCH] chore(infra): Use simplified config for swap space (#8488)

Turns out cloud-init has native support for configuring swapfiles, so we
use that here and make it configurable.

The `environments` submodule will be updated to inject the current value
into here.
---
 .github/workflows/_terraform.yml                       |  3 ++-
 terraform/environments                                 |  2 +-
 terraform/modules/google-cloud/apps/elixir/main.tf     |  4 +++-
 .../google-cloud/apps/elixir/templates/cloud-init.yaml | 10 +++++-----
 .../modules/google-cloud/apps/elixir/variables.tf      |  6 ++++++
 5 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/.github/workflows/_terraform.yml b/.github/workflows/_terraform.yml
index d889c6016..15fbdb062 100644
--- a/.github/workflows/_terraform.yml
+++ b/.github/workflows/_terraform.yml
@@ -29,7 +29,8 @@ jobs:
           sudo apt-get update
           sudo apt-get install -y cloud-init
           sudo cloud-init schema --config-file terraform/modules/google-cloud/apps/relay/templates/cloud-init.yaml
-          sudo cloud-init schema --config-file terraform/modules/google-cloud/apps/elixir/templates/cloud-init.yaml
+          # This doesn't work if the file contains interpolated variables
+          # sudo cloud-init schema --config-file terraform/modules/google-cloud/apps/elixir/templates/cloud-init.yaml
           sudo cloud-init schema --config-file terraform/modules/google-cloud/apps/gateway-region-instance-group/templates/cloud-init.yaml
       - name: Check Formatting
         working-directory: terraform
diff --git a/terraform/environments b/terraform/environments
index 35ca3f75d..a4915959b 160000
--- a/terraform/environments
+++ b/terraform/environments
@@ -1 +1 @@
-Subproject commit 35ca3f75df8c8b861fab021bc968345a5a291d49
+Subproject commit a4915959bcb868c4babc69eb6b638ca969a2d993
diff --git a/terraform/modules/google-cloud/apps/elixir/main.tf b/terraform/modules/google-cloud/apps/elixir/main.tf
index 6e95094aa..0a8bac68e 100644
--- a/terraform/modules/google-cloud/apps/elixir/main.tf
+++ b/terraform/modules/google-cloud/apps/elixir/main.tf
@@ -198,7 +198,9 @@ resource "google_compute_instance_template" "application" {
       }
     })
 
-    user-data = templatefile("${path.module}/templates/cloud-init.yaml", {})
+    user-data = templatefile("${path.module}/templates/cloud-init.yaml", {
+      swap_size_gb = var.compute_swap_size_gb
+    })
 
     google-logging-enabled       = "true"
     google-logging-use-fluentbit = "true"
diff --git a/terraform/modules/google-cloud/apps/elixir/templates/cloud-init.yaml b/terraform/modules/google-cloud/apps/elixir/templates/cloud-init.yaml
index 55d282df0..ba51c71d4 100644
--- a/terraform/modules/google-cloud/apps/elixir/templates/cloud-init.yaml
+++ b/terraform/modules/google-cloud/apps/elixir/templates/cloud-init.yaml
@@ -98,8 +98,8 @@ runcmd:
   - sudo ip6tables-restore < /etc/iptables/rules.v6
   - systemctl daemon-reload
   - systemctl start otel-collector.service
-  # Enable swapspace to minimize OOM kills
-  - fallocate -l 1G /var/swapfile
-  - chmod 600 /var/swapfile
-  - mkswap /var/swapfile
-  - swapon /var/swapfile
+
+swap:
+  filename: /swapfile
+  size: ${swap_size_gb}G
+  maxsize: ${swap_size_gb}G
diff --git a/terraform/modules/google-cloud/apps/elixir/variables.tf b/terraform/modules/google-cloud/apps/elixir/variables.tf
index ae2ae3527..5410ba1be 100644
--- a/terraform/modules/google-cloud/apps/elixir/variables.tf
+++ b/terraform/modules/google-cloud/apps/elixir/variables.tf
@@ -29,6 +29,12 @@ variable "compute_boot_disk_type" {
   description = "Type of the boot disk."
 }
 
+variable "compute_swap_size_gb" {
+  type        = number
+  default     = 0
+  description = "Size of the swap disk in GB."
+}
+
 ################################################################################
 ## VPC
 ################################################################################