Kubernetes CronJob monitoring sounds simple until the first scheduled job silently does not run. Your cluster is healthy. The pods look fine. The app is serving traffic. Prometheus is green. Then somebody asks why yesterday’s invoices were not generated, why cleanup did not happen, or why a customer export is missing. The problem is that Kubernetes can tell you a lot about pods and workloads, but a scheduled job is different: it matters that it ran at the right time, completed successfully, and keeps doing that every time. This guide explains what actually breaks with Kubernetes CronJobs, why missed runs are easy to miss, and how to monitor them with heartbeat checks. The problem A Kubernetes CronJob is a scheduled workload. You define a schedule, Kubernetes creates Jobs, and those Jobs create Pods.…