Track 5 · Design Interview Problems
Design Distributed Job Scheduler (Cron at Scale)
Distributed task and cron execution at enterprise scale. Hierarchical timing wheels, distributed leader locks, and guaranteed single execution under network drops.
Interview problem25 min read1 interactive
On this page
- Problem framing
- Questions I ask before drawing anything
- Requirements
- Estimation
- API design
- Database schema
- The data structures of time: Timing Wheels vs Redis ZSET
- Evolutionary architecture: v1 MVP to v2 Distributed scale
- System architecture deep dives
- The critical failure mode: lost ack and safe retries
- Edge cases and failure recovery
- Cross-questions interviewers will ask
- Interview Rubric: Mid-Level vs Senior / Staff