Enable budget alerts on azure clusters

docs/howto/budget-alerts.md

@@ -3,11 +3,9 @@
 
 This document describes how to enable budget alerts for a cluster.
 
-```{note}
-This feature is currently only available on GCP!
-```
-
-## GCP
+`````{tab-set}
+````{tab-item} GCP
+:sync: gcp-key
 
 ```{attention}
 We can only enable budget alerting on GCP projects where we have enough permissions to enable APIs and view the billing account.
@@ -31,3 +29,28 @@ Then edit the following variables in the relevant `.tfvars` file for the cluster
     In this case, we cannot enable budget alerting for this project.
 
 With these variables set, you are ready to open a PR and perform a terraform apply!
+````
+
+````{tab-item} Azure
+:sync: azure-key
+
+To enable budget alerts for an Azure cluster, edit the following variables in the relevant `.tfvars` file for the cluster.
+
+- **Set `budget_alert_enabled = true`**
+
+  This will ensure that the relevant resources will be created by terraform.
+
+- **Set `budget_alert_amount`**
+
+  Current practice is to set this to the average expenditure of the last 3 months.
+
+  Then the alert will be triggered when the forecasted cost will exceed this value plus 20%.
+
+  You can find values to calculate that in the Cost analysis tab of the relevant Azure subscription: `Azure subscription` -> `Cost Management` -> `Cost analysis`.
+
+  If you are setting this up for a new cluster, you obviously don't have this information yet!
+  Instead, set the value to something like `500` and we can adjust as the community begins to use it.
+
+- With these variables set, you are ready to open a PR and perform a terraform apply!
+````
+`````

terraform/azure/budget-alerts.tf

@@ -0,0 +1,24 @@
+data "azurerm_subscription" "current" {}
+resource "azurerm_consumption_budget_subscription" "budget" {
+  name            = "BudgetSubscription-${var.resourcegroup_name}"
+  subscription_id = data.azurerm_subscription.current.id
+
+  amount     = var.budget_alert_amount
+  time_grain = "Monthly"
+
+  time_period {
+    start_date = "2024-07-01T00:00:00Z"
+    end_date   = "2029-07-01T00:00:00Z"
+  }
+
+  notification {
+    enabled        = var.budget_alert_enabled ? true : false
+    threshold      = 120
+    operator       = "GreaterThanOrEqualTo"
+    threshold_type = "Forecasted"
+
+    contact_emails = [
+      "support+budget-${var.resourcegroup_name}@2i2c.org",
+    ]
+  }
+}

terraform/azure/projects/pchub.tfvars

@@ -22,6 +22,10 @@ global_container_registry_name = "2i2cpchub"
 global_storage_account_name    = "2i2cpchub"
 location                       = "westeurope"
 
+budget_alert_enabled = true
+# This is approximate total cost for Jun 2024 in USD
+budget_alert_amount = "500"
+
 storage_size = 100
 ssh_pub_key  = "ssh-rsa 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 [email protected]"
 

terraform/azure/variables.tf

@@ -172,3 +172,20 @@ variable "fileshare_alert_available_fraction" {
   Decimal fraction (between 0 and 1) of total space available in fileshare. If used space is over this, we fire an alert to pagerduty.
   EOT
 }
+
+variable "budget_alert_enabled" {
+  type        = bool
+  default     = false
+  description = <<-EOT
+  Enable budget alerts. Disable in cases where we do not have enough permissions
+  on the billing account or cloud account to enable APIs.
+  EOT
+}
+
+variable "budget_alert_amount" {
+  type        = string
+  description = <<-EOT
+  Amount of *forecasted spend* at which to send a billing alert. Current practice
+  is to set this to the average of the last 3 months expenditure + 20%.
+  EOT
+}