Route HTTP requests to pods in a cluster
Company: Turo
Role: Software Engineer
Category: System Design
Difficulty: medium
Interview Round: Technical Screen
In a Docker/Kubernetes-like container cluster running multiple replicas (pods) of a service, explain how an incoming HTTP request reaches a specific pod.
Cover the end-to-end flow and components such as:
- External entry point (DNS, ingress/reverse proxy, L4/L7 load balancer)
- Service abstraction / virtual IP
- Service discovery and service registry (how instances are registered and discovered)
- Load-balancing algorithms and health checks
Then address failure handling:
- What can go wrong if a request fails between services/pods (e.g., mid-hop failure, timeout, partial execution)?
- How would you implement retries with backoff safely?
- How do you avoid duplicate side effects (idempotency, deduplication) and handle cascading failures (timeouts, circuit breakers)?
Quick Answer: This question evaluates understanding of request routing, service discovery, virtual service abstractions, load balancing algorithms, health checks, and fault-tolerance mechanisms within containerized cluster environments, testing competencies in distributed systems and networked service architecture.