#fault tolerance

12 fault tolerance interview questions, asked at Google, Databricks, Amazon and 6 more companies. Last asked Sep 2026.

Design a lab machine fleet monitor with remote rebootSystem designDesign a service that watches a fleet of lab machines running compute workloads. Each machine polls the service for work; a work item names a payload the machine must download…
Last asked Sep 2026
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Design a video generation service on a scarce GPU poolAI system designUsers submit text-to-video requests that each need minutes of GPU time, and the GPU pool is limited and changes size. Design the request flow, scheduling and workers, how users…
Last asked Sep 2026
Design a workflow orchestration systemSystem designUsers define a workflow as steps with dependencies, then start runs of it. Design the system that runs each step once its dependencies finish, records the state of every run and…
Last asked Sep 2026
Coordinate a fleet of restaurant robotsSystem designDesign the system that coordinates many robots working in a restaurant. Start by pinning down what work the robots do, then cover how tasks are assigned, how execution state is…
Last asked Sep 2026
Design a distributed file system for large structured datasetsSystem designDesign a distributed file system or storage service for large structured datasets that data-processing jobs read and write. Go past the box diagram and walk through the concrete…
Last asked Sep 2026
Primary and secondary circuit breakers with failoverCodingA service reads from a primary backend and can fail over to a secondary backend (for example a leader database and a follower). Put a circuit breaker in front of each backend so…
Last asked Aug 2026
Design a durable cron job schedulerSystem designDesign a service that runs recurring jobs on cron-style schedules and does not lose them when machines fail. Cover how schedules are stored and turned into the next run time, how…
Last asked Apr 2026
Design guardrails and fallbacks for a reliable LLM serviceAI system designA product depends on calls to a large language model. Design the guardrails and fallback paths that keep it reliable: what you check on the way in and on the way out, what the…
Last asked Feb 2026
Design a dependency-aware job schedulerSystem designDesign a job scheduler in which each job is a list of tasks with dependencies between them; a task may start only when every task it depends on has finished. Cover how you…
Last asked Jan 2026
Design a menu update system for a global restaurant chainSystem designHeadquarters controls the menus shown on many kinds of devices in restaurants worldwide. Menus share global items but have local parts per country, and they change for breakfast…
Last asked Nov 2025
Design a distributed task scheduler with dependenciesSystem designDesign a system that runs jobs made of tasks with dependencies between them, including long-running tasks. Cover how jobs and their dependency graphs are stored, how ready tasks…
Last asked Sep 2025
Design a protocol for distributed transactionsSystem designA transaction must update data held by several independent services or shards, so that either all changes happen or none do. Design the protocol: how participants agree to commit…
Last asked Sep 2025