Update instructions

Author: lorenyu

docs/infra/set-up-monitoring-alerts.md

@@ -4,26 +4,21 @@
 
 The monitoring module defines metric-based alerting policies that provide awareness into issues with the cloud application. The module supports integration with external incident management tools like Splunk-On-Call or Pagerduty. It also supports email alerts.
 
-### Set up email alerts.
-
-1. Add the `email_alerts_subscription_list` variable to the monitoring module call in the service layer
-
-For example:
-```
-module "monitoring" {
-  source = "../../modules/monitoring"
-  email_alerts_subscription_list = ["email1@email.com", "email2@email.com"]
-  ...
-}
-```
+### Set up email alerts
+
+The monitoring module supports a simple email-based alerting system that does not rely on an external incident management service.
+
+1. Update the `email_alert_recipients` variable in `app-config/env-config/monitoring.tf`
+
 2. Run `make infra-update-app-service APP_NAME=<APP_NAME> ENVIRONMENT=<ENVIRONMENT>` to apply the changes to each environment.
-When any of the alerts described by the module are triggered notification will be sent to all emails specified in the `email_alerts_subscription_list`
 
-### Set up External incident management service integration.
+### Integrate with an incident management service
 
 1. Set setting `has_incident_management_service = true` in app-config/main.tf
 2. Get the integration URL for the incident management service and store it in AWS SSM Parameter Store by running the following command for each environment:
-```
-make infra-configure-monitoring-secrets APP_NAME=<APP_NAME> ENVIRONMENT=<ENVIRONMENT> URL=<WEBHOOK_URL>
-```
+
+    ```bash
+    make infra-configure-monitoring-secrets APP_NAME=<APP_NAME> ENVIRONMENT=<ENVIRONMENT> URL=<WEBHOOK_URL>
+    ```
+
 3. Run `make infra-update-app-service APP_NAME=<APP_NAME> ENVIRONMENT=<ENVIRONMENT>` to apply the changes to each environment.

infra/app-rails/app-config/env-config/monitoring.tf

@@ -2,7 +2,7 @@ locals {
   monitoring_config = {
     # Emails to notify for alerts.
     # Use this as a simple notification mechanism if you don't have an incident management service.
-    # email_alert_recipients = ["email1@email.com", "email2@email.com"]
+    email_alert_recipients = []
 
     incident_management_service = var.has_incident_management_service ? {
       integration_url_param_name = "/monitoring/${var.app_name}/${var.environment}/incident-management-integration-url"

infra/app/app-config/env-config/monitoring.tf

@@ -2,7 +2,7 @@ locals {
   monitoring_config = {
     # Emails to notify for alerts.
     # Use this as a simple notification mechanism if you don't have an incident management service.
-    # email_alert_recipients = ["email1@email.com", "email2@email.com"]
+    email_alert_recipients = []
 
     incident_management_service = var.has_incident_management_service ? {
       integration_url_param_name = "/monitoring/${var.app_name}/${var.environment}/incident-management-integration-url"