Notification Routing with SNS and User Notifications
Explore the process of setting up notification routing in AWS using SNS topics, subscriptions, and CloudWatch alarm actions. Learn to trace notification delivery with proof points, diagnose common routing failures, and establish operational contracts for reliable incident response. This lesson equips you to manage and verify notification paths effectively for alerting in production environments.
An incident doesn't care that a CloudWatch alarm changed state if no human or system actually received a notification. The failure sits at the boundary between signal and delivery, where an alarm can be correct, an on-call schedule can be correct, and the page still never arrives.
Reasoning about that boundary means keeping the minimum routing chain in view. A CloudWatch alarm invokes an action, that action targets an SNS topic, and that topic attempts delivery to a subscription endpoint, such as email, an HTTPS webhook, or a chat integration. Where AWS User Notifications is in use, it functions as an aggregation and management surface for user-facing notifications, but it still requires evidence that delivery occurred, rather than assuming visibility equals delivery.
Tracing the notification path with evidence
A notification path is a sequence of state transitions, and each transition leaves a different kind of proof. When an alarm transitions from OK to ALARM, or back, CloudWatch records an action attempt in the alarm history. When SNS receives a publish, SNS updates topic-level metrics and then attempts delivery to each subscription, which has its own confirmation state and delivery ...