How would you debug production issues related to L4 vs L7 Load Balancing?

Answers use simple, clear English.

Quick interview answer

Debug L4 vs L7 Load Balancing by confirming blast radius, checking lag/error metrics, grabbing profiles/traces, then mitigating before deep root-cause. Baseline: L4 (TCP) routes by IP/port fast. L7 (HTTP) routes by path/header/cookie — enables sticky sessions, TLS, WAF integration.

Detailed answer

Production debug playbook for L4 vs L7 Load Balancing: 1) Stabilize: rate-limit, shed load, or roll back if users are hurting. 2) Orient: dashboards for latency, errors, saturation tied to L4 vs L7 Load Balancing. 3) Evidence: traces, profiles, logs with correlation IDs. 4) Hypothesize + prove with a safe experiment. 5) Fix + add a regression test/alert so it cannot silently return. Watch for: L7 LB without health checks; single LB bottleneck. 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

Interviewers score structured incident thinking: mitigate → measure → root cause → prevent. L4 (TCP) routes by IP/port fast. L7 (HTTP) routes by path/header/cookie — enables sticky sessions, TLS, WAF integration.

Follow-up questions

Only answered follow-ups are shown — click to open with full answers

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.

View full parent question →

#sd-load-balancer-layers#junior