Health Checks That Lied

Our pods report healthy but can't serve traffic. How?

The health check:

livenessProbe:
                                    httpGet:
                                    path: /health
                                    port: 8080

The handler:

@GetMapping("/health")
                                    public String health() {
                                    return "OK";  // Always returns OK
                                    }

The problem:

• App starts, returns "OK"
• Database connection fails
• Cache unreachable
• External API timeout
• But health check: "OK" ✅

The better approach:

@GetMapping("/health/ready")
                                    public ResponseEntity<HealthStatus> readiness() {
                                    boolean dbOk = checkDatabase();
                                    boolean cacheOk = checkCache();
                                    if (dbOk && cacheOk) {
                                    return ResponseEntity.ok(status);
                                    }
                                    return ResponseEntity.status(503).body(status);
                                    }

Lesson: A health check that doesn't check health is worse than no health check.

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