Reliability

Your application says it’s running. But is it actually working? Health checks answer that question. They’re the difference between “process exists” and “service is functional.” Get them wrong, and your orchestrator will either route traffic to broken instances or restart healthy ones. Three Types of Probes Liveness: “Is this process stuck?” Liveness probes detect deadlocks, infinite loops, and zombie processes. If liveness fails, the container gets killed and restarted. 1 2 3 4 5 6 7 livenessProbe: httpGet: path: /healthz port: 8080 initialDelaySeconds: 30 periodSeconds: 10 failureThreshold: 3 What to check: ...

Kill -9 is violence. Your application deserves a dignified death. Graceful shutdown means finishing in-flight work before terminating. Without it, deployments cause dropped requests, broken connections, and data corruption. With it, users never notice you restarted. The Problem When a process receives SIGTERM: Kubernetes/Docker sends the signal Your app has a grace period (default 30s) After the grace period, SIGKILL terminates forcefully If your app doesn’t handle SIGTERM, in-flight requests get dropped. Database transactions abort. WebSocket connections die mid-message. ...