Reliability and Operational Excellence Questions

Covers design and operational practices for building and running reliable software systems and for achieving operational maturity. Topics include defining, measuring, and using Service Level Objectives, Service Level Indicators, and Service Level Agreements; establishing error budget policies and reliability governance; measuring incident impact and using error budgets to prioritize work. Also includes architectural and operational techniques such as redundancy, failover, graceful degradation, disaster recovery, capacity planning, resilience patterns, and technical debt management to improve availability at scale. Operational practices covered include observability, monitoring, alerting, runbooks, incident response and post incident analysis, release gating, and reliability driven prioritization. Proactive resilience practices such as fault injection and chaos engineering, as well as trade offs between reliability, cost, and development velocity and scaling reliability practices across teams and organizations, are included to capture both hands on and senior level discussions.

MediumTechnical

87 practiced

Your service is forecasted to grow 3x in traffic over the next six months. Outline a capacity planning approach that includes the telemetry you will monitor, the cadence of load testing, autoscaling policy decisions, cost mitigation (reserved vs on-demand), and contingency runbooks for sudden unexpected spikes.

EasyTechnical

138 practiced

List the typical steps in capacity planning for an online service: measurement, forecasting, setting headroom, and procurement or autoscaling decisions. For each step provide one example metric and explain how it's used (for example: 95th-percentile CPU for headroom).

HardSystem Design

91 practiced

Design an SLO-based release gating system that can scale across hundreds of services. Describe the architecture (centralized vs decentralized), how SLIs are ingested and validated, enforcement mechanisms (CI/CD pre-deploy checks, automated gating), handling of flaky metrics and partial outages, and how teams are onboarded or may opt-in/opt-out.

MediumSystem Design

103 practiced

Design alert routing and escalation rules for a company with ~20 services and 5 platform teams. Explain principles for routing to service owners, escalation timelines, on-call rotations, how to reduce blind spots, and how to handle overlapping pager responsibilities or out-of-hours coverage.

EasyTechnical

136 practiced

Explain the three pillars of observability—metrics, logs, and traces. For each pillar give one concrete example of telemetry you would collect for a low-latency HTTP service and explain briefly how that artifact helps you find the root cause of a high-latency request.

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