عرض عملي: توسيع خدمة المخزون إلى ثلاث نسخ

خطوة بخطوة

1. Start Shop with docker compose up --scale inventory=3; remove fixed host port mappings from inventory.
2. Call inventory from orders repeatedly and log the replica's hostname; show requests spread across three.
3. Run a load test; kill one replica mid-run.
4. Planned mistake: hard-code one replica's IP in orders config. When that replica dies, every call fails. Fix: use the service name.
5. Show errors limited to requests in flight on the killed replica; explain why (already sent, not yet rerouted) and how retries on idempotent calls plus graceful shutdown reduce it.