Most AWS accounts have dozens of CloudWatch alarms and about three anyone trusts. A practical guide to missing-data settings, M-out-of-N evaluation, metric math, composite alarms and mute rules, and how to test the notification path before you need it.
Your SaaS pipeline will fail far more often by succeeding at nothing than by throwing an exception, and every CloudWatch default treats an absent metric as a non-event. Here are the four signals worth alarming on: liveness, volume, freshness and shape, plus the missing-data traps that leave alarms permanently green.
A SaaS admin changes a field and your pipeline stays green while the numbers drift. A practical guide to AWS Glue Data Quality for SaaS sources: where to run the checks, why nested payloads need flattening before DQDL can see them, which rule catches which failure, and the dynamic rules that pass silently because they have no history yet.