All bites
The whole library, newest first. Filter by what you are here for, or pick a topic if you already know.
4330 bites
Page 210
Designing an error budget policy
Define SLO and budget, tiered consequences as burn worsens, a feature freeze on exhaustion, and concrete earn-back criteria.
Calculating downtime for a 99.9% SLO
0.1% of 30 days is roughly 43 minutes of allowed downtime; healthy budget enables faster shipping while depletion slows or freezes deploys.
Writing high-quality postmortem action items
Good action items are specific, assigned to an owner, prioritized, tracked to completion, and ideally prevent recurrence rather than just detect faster.
Rolling update vs blue-green deployment
Rolling replaces instances gradually with minimal extra capacity but mixes versions; blue-green runs two full environments for instant switch and rollback at double the cost.
Designing shallow vs deep health checks
Shallow checks confirm the process is alive; deep checks verify dependencies; use shallow for liveness/load-balancer routing and deep sparingly to avoid…
First-SRE 90-day plan at a startup
Listen and measure first, pick one high-impact service, define SLIs/SLOs and basic alerting, then show reduced toil or incidents to leadership.
OpenTelemetry agent and gateway architecture
Agents run per-node for local collection and host enrichment; gateways are central, horizontally scaled pools for batching, tail sampling, and routing.
Key roles in incident response
Incident Commander coordinates and decides but does not fix; Communications Lead handles stakeholders; Operations/SMEs do hands-on diagnosis and remediation.
Breaking tunnel vision during an incident
Call out the assumption, ask for disconfirming evidence, list parallel hypotheses, split responders to investigate them, and anchor on what changed and the data.
Safeguards for automated remediation runbooks
Add rate limits and circuit breakers on restarts, escalate to humans after N attempts, log all actions, and check for cascading failure before acting.
Automating actions on error budget burn
Use multi-window burn-rate alerts; on fast burn, auto-trigger actions like halting deploys, rolling back, or scaling, with escalating tiers.
Managing a risky release with feature flags
Deploy code dark behind an off flag, enable for internal then small percentage, monitor metrics, ramp gradually, then remove the flag.
Designing a feature flagging service
Control plane (UI, store, targeting), SDKs that cache flags locally for zero-latency evaluation, streaming/CDN delivery for near-real-time updates, and stale-flag lifecycle tooling.
Capacity planning for distributed stateful systems
Account for replication and cross-region network, IOPS and disk throughput, connection limits, partition/shard balance, and N+1 region failover headroom; validate with load and chaos…
Capacity planning for a distributed cache
Track hit ratio, memory and eviction rate, throughput/latency, and connections; correlate with growth to forecast when to add capacity before the hit ratio or evictions…
Federating reliability ownership to product teams
Build a self-service reliability platform (golden paths, paved roads), train teams and embed SLO/on-call practices, and govern with standards plus error budget…
What is the difference between primary, foreign, and unique keys?
This tests relational integrity basics. Answer: primary keys identify rows, foreign keys reference tables, and unique keys are alternate candidates. Red flag: saying unique keys are just for indexing or omitting a non-PK example like email.
Explain ACID properties and why they matter for banking or e-commerce
Define each as a failure-handling guarantee; show how partial commits cause double-spending.
What is the difference between DDL and DML in SQL?
DDL shapes schema with CREATE or ALTER; DML handles row-level data with SELECT, INSERT, UPDATE, or DELETE.
Describe 1NF, 2NF, 3NF, normalization's purpose, and its performance trade-off.
1NF atomic values; 2NF no partial dependencies; 3NF no transitive dependencies; prevents update anomalies but adds join overhead.