DevOps Monitoring & Observability 1 — Questions and Answers
Question 1: What are the 'three pillars of observability'?
- Logs, metrics, and traces (Correct answer)
- Alerts, dashboards, and incidents
- Uptime, latency, and throughput
- Monitoring, logging, and auditing
Correct answer: Logs, metrics, and traces
The three pillars of observability are logs (event records), metrics (numeric measurements over time), and distributed traces (request flows across services).
Question 2: What is Prometheus primarily used for in a DevOps environment?
- Collecting and storing time-series metrics with a pull-based model (Correct answer)
- Aggregating and searching application logs across services
- Distributed tracing of requests across microservices
- Alerting on infrastructure security vulnerabilities
Correct answer: Collecting and storing time-series metrics with a pull-based model
Prometheus is an open-source monitoring system that scrapes metrics from instrumented targets at defined intervals and stores them as time-series data.
Question 3: What is Grafana used for?
- Visualizing metrics and logs from data sources like Prometheus in dashboards (Correct answer)
- Collecting application logs from distributed services
- Running load tests against production systems
- Tracing distributed requests across microservices
Correct answer: Visualizing metrics and logs from data sources like Prometheus in dashboards
Grafana is an open-source visualization and analytics platform that connects to data sources like Prometheus, Elasticsearch, and CloudWatch to create dashboards.
Question 4: What is an SLO (Service Level Objective)?
- A target reliability or performance goal for a service, expressed as a measurable metric (Correct answer)
- A contractual agreement between a provider and customer about service uptime
- A threshold that triggers an alert when a metric exceeds it
- A budget for acceptable downtime over a given period
Correct answer: A target reliability or performance goal for a service, expressed as a measurable metric
An SLO is an internal reliability target (e.g., 99.9% availability) that teams use to guide engineering decisions and prioritize reliability work.
Question 5: What is an 'error budget' in Site Reliability Engineering (SRE)?
- The permissible amount of unreliability remaining before an SLO is violated (Correct answer)
- The cost allocated for fixing production incidents
- The maximum number of errors allowed per minute in production
- The time budget for on-call engineers to respond to incidents
Correct answer: The permissible amount of unreliability remaining before an SLO is violated
An error budget is 100% minus the SLO — if your SLO is 99.9% availability, your error budget is 0.1% downtime per period.
Question 6: What does MTTR stand for in incident management?
- Mean Time to Recovery — average time to restore service after an incident (Correct answer)
- Mean Time to Report — average time to notify stakeholders of an incident
- Maximum Time to Resolve — SLA-defined resolution deadline
- Mean Time to Respond — average time for on-call to acknowledge an alert
Correct answer: Mean Time to Recovery — average time to restore service after an incident
MTTR (Mean Time to Recovery) measures the average elapsed time between a system failure and full service restoration, indicating incident response effectiveness.
DevOps Monitoring & Observability 1
What are the 'three pillars of observability'?