System design interview question
Design a Distributed Job Scheduling & Execution Platform (like Airflow or Temporal at Scale)
Design a fault-tolerant, globally distributed job scheduling and execution platform that handles 500K concurrent job executions across multiple data centers. The system must support complex DAG-based workflows, handle job retries with exponential backoff, persist execution state reliably, and provide at-least-once execution semantics with idempotency guarantees. Candidate should design for 10K job submissions/second, 50M total jobs in the system, and sub-second scheduling latency for priority queues. Key constraints include: handling worker failures and network partitions, preventing duplicate executions, supporting dynamic scaling of worker pools, and maintaining audit logs for compliance. The platform must be extensible for custom job types and integrations with external systems (databases, APIs, message queues).
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