Infrastructure Primitives
Design a Distributed Task Scheduler
A cron-like scheduler that reliably triggers and executes millions of delayed or recurring jobs exactly once across a worker fleet.
Open and Simulate this Architecture in InfraDraftCore Architectural Components
Job Definition Store
Persists cron expressions, delay metadata, and job payloads.
Time-Wheel / Priority Queue Scheduler
Efficiently finds the next job due to fire without scanning the whole job set.
Leader Election for Trigger Node
Ensures only one node fires a given scheduled job, avoiding duplicates.
Worker Pool with Lease-Based Claiming
Workers claim jobs with a lease so a crashed worker's job gets picked up by another.
Dead-Letter Queue
Captures jobs that fail repeatedly for manual inspection instead of infinite retry.
Idempotency Key Store
Guarantees exactly-once execution semantics even under retries.
Job Execution Audit Log
Records every trigger, success, and failure for observability.