Design config rollout and click aggregation
Company: Netflix
Role: Data Engineer
Category: System Design
Difficulty: hard
Interview Round: Onsite
The system design rounds included two prompts:
1. **Global configuration deployment**
- Design a system that allows engineers to publish configuration changes and roll them out safely to services running in many regions worldwide.
- Support versioning, staged rollout, rollback, validation, audit history, and fast propagation.
- Explain how to balance safety, consistency, and rollout speed.
2. **Ads click event aggregation**
- Design a system that ingests a very high volume of ad click events and produces aggregated metrics such as counts per campaign, ad, region, and time window.
- Support near-real-time dashboards, fault tolerance, deduplication, late-arriving events, and horizontal scaling.
Quick Answer: This question evaluates system design and data engineering competencies, focusing on distributed systems, global configuration management, deployment safety (versioning, staged rollout, rollback), and high-throughput event ingestion and aggregation for real-time metrics.