Follow-up · depth 2
What metrics prove L4 vs L7 Load Balancing is healthy in prod?
What metrics prove L4 vs L7 Load Balancing is healthy in prod?
Answers use simple, clear English.
Audio N/AQuick interview answer
Prove L4 vs L7 Load Balancing is healthy with latency (p50/p95/p99), error/saturation rates, and queue/event-loop lag — not just CPU. Context: Baseline: L4 (TCP) routes by IP/port fast. L7 (HTTP) routes by path/header/cookie — enables sticky sessions, TLS, WAF integration.
Detailed answer
Production health signals for L4 vs L7 Load Balancing: • Latency: p50/p95/p99 of the critical path that uses L4 vs L7 Load Balancing. • Errors: failure rate, timeouts, and retry storms. • Saturation: queue depth, event-loop delay, thread/pool utilization. • Business SLIs: request success and user-visible freshness where relevant. Trade-off lens: Pros: L7 smart routing; L4 performance for non-HTTP. Cons: L7 terminates TLS — cert management; L4 no URL awareness. Explain thresholds + alerts, then how you triage. Parent context: Baseline: L4 (TCP) routes by IP/port fast. L7 (HTTP) routes by path/header/cookie — enables sticky sessions, TLS, WAF integration.
Full explanation
Good answers name measurable signals and what “bad” looks like for L4 vs L7 Load Balancing. L4 (TCP) routes by IP/port fast. L7 (HTTP) routes by path/header/cookie — enables sticky sessions, TLS, WAF integration.
Follow-up questions
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Parent context — L4 vs L7 Load Balancing
Baseline: L4 (TCP) routes by IP/port fast. L7 (HTTP) routes by path/header/cookie — enables sticky sessions, TLS, WAF integration.
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