This one threw me a bit because you have to think about it from two angles at once: the distributed systems side and the adversarial/security side.
First, clarify that a botnet-based crawler is unethical and illegal, then pivot to designing a distributed crawler using consented, owned, or cloud infrastructure. Focus on the technical architecture: distributed nodes, coordination, deduplication, and politeness, while emphasizing legal and ethical constraints.
Pro tip: Demonstrate maturity by explicitly rejecting the botnet premise and proposing a legitimate distributed crawler; this shows you prioritize ethics and legal compliance, which Snap values.
Acknowledge the unethical nature of botnets and propose designing a distributed crawler using legitimate infrastructure like cloud VMs or volunteered devices with consent.
Estimate scale (pages per second, storage, bandwidth) and define goals: freshness, coverage, politeness, and fault tolerance.
Outline components: coordinator (scheduler), worker nodes (crawlers), distributed queue (e.g., Kafka), storage (e.g., S3, BigTable), and deduplication (Bloom filters).
Explain how to distribute URLs, avoid overloading sites (rate limiting per domain), handle failures, and ensure exactly-once processing.
Compare centralized vs. decentralized coordination, discuss CAP theorem implications, and emphasize robots.txt, terms of service, and data privacy.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.