Observability: Grafana, Logs & Traces
The pillars beyond metrics, explained from first principles. Learn the three signals, structured logging and Loki, distributed tracing, OpenTelemetry and Grafana — and remember it with spaced repetition.
- flashcards
- 62
- flashcards
- per day
- ~10 min
- per day
- level
- Beginner → Intermediate
- level
- modules
- 5
- modules
What is observability?
Observability is the ability to understand what is happening inside a system from the telemetry it emits — enough to debug problems you did not anticipate, not just the ones you set alerts for. It rests on three signals: metrics (aggregatable numbers over time), logs (discrete timestamped events), and traces (the causal path of one request across services). Each answers a different question, and the real skill is knowing which to reach for.
Metrics are the province of the Prometheus track; this track covers everything around them. It grounds the RED and USE methods, then goes deep on the other two pillars: structured logging and how Grafana Loki stays cheap by indexing labels instead of full text, and distributed tracing — spans, context propagation, and head- vs tail-based sampling with backends like Tempo and Jaeger.
It ties the picture together with OpenTelemetry — the vendor-neutral standard for producing telemetry, its Collector pipeline and OTLP — and Grafana, the layer where you visualize and alert on all of it. Spaced repetition keeps the concepts sharp for when you are on call and need them most.
Studying for a certification? This track is the core of the OpenTelemetry Certified Associate blueprint — its API-and-SDK domain alone is 46 % of that exam. It also covers the part of the Prometheus Certified Associate paper that is not about Prometheus: traces, spans and logs make up an 18 % domain there.
5 modules, seed to bloom
Each module is a set of flashcards — 62 in total. Answer, review, and watch your knowledge grow from seed to full bloom.
Three Pillars & Signals
metrics, logs and traces — what each signal is for
10 cardsLogs & Loki
structured logging, Loki architecture and LogQL
11 cardsDistributed Tracing
spans, context propagation, sampling, Tempo and Jaeger
11 cardsOpenTelemetry
OTel API/SDK, the Collector, OTLP and instrumentation
19 cardsGrafana
dashboards, panels, data sources, variables and alerting
11 cardsSample questions
A taste of the real flashcards. Pick an answer, then reveal the explanation.
What are the three primary telemetry signals in observability?
- AMetrics, logs and traces
- BMetrics, logs and profiles
- CMetrics, traces and dashboards
- DCounters, gauges and histograms
What does Loki read when you grep a week of logs?
- AThe chunks of the streams your labels matched, decompressed and scanned
- BThe full-text index, which resolves the string to matching entries
- CEvery chunk in the store, since labels do not narrow a text search
- DThe compactor's summary table, which records the strings it has seen
A 300 ms trace holds a 250 ms database span. What does that show?
- AWhere the time went — that call dominates the request
- BThat the database is saturated — it needs more capacity
- CThat the other spans ran concurrently — alongside the query
- DNothing yet — a span's duration excludes time spent waiting
You switch vendors after instrumenting with OTel. What changes?
- AThe exporter configuration — the instrumentation itself stays put
- BEvery call site — the instrumentation names the vendor
- CThe whole SDK — each vendor ships its own implementation
- DNothing at all — a vendor reads OTLP straight from the application
Learn it once, keep it for good
Answer a question
Each card is one practical concept with multiple options. Pick what you think is right.
Get the full answer
See the correct option plus a clear explanation, and a link to deeper docs when one is available.
Review at the right time
A spaced-repetition engine (SM-2 or FSRS) resurfaces each card just before you would forget it.
Why observability is worth your time
Debug the unknown-unknowns
Knowing when to reach for a metric, a log or a trace is what lets you diagnose novel failures instead of guessing.
Vendor-neutral by design
OpenTelemetry and the Grafana stack are open standards — the skills transfer across employers and tools.
Control logging cost
Understanding Loki labels and cardinality is how you keep logs queryable without an eye-watering bill.
A core SRE and platform skill
The three pillars, tracing and OpenTelemetry are staple topics in SRE, DevOps and platform interviews.
Common questions
How is this different from the Prometheus track? +
The Prometheus track owns metrics — PromQL, metric types, exporters and Alertmanager. This track covers the other two pillars (logs and traces), OpenTelemetry, and Grafana, so the two are siblings that together complete the observability picture.
Do I need monitoring experience first? +
No. The track starts from what observability means and the three signals, so beginners and engineers formalizing what they already half-know both benefit.
Does it cover OpenTelemetry and Grafana? +
Yes. Dedicated modules cover OpenTelemetry (the API/SDK, the Collector pipeline, OTLP and instrumentation) and Grafana (dashboards, data sources, variables and unified alerting), alongside logs/Loki and distributed tracing.
Is it free? +
Yes, completely free. No registration or credit card is required, and all your progress is stored locally in your browser.
Ready to master observability?
Plant your first seed today. Ten minutes a day is all it takes to turn telemetry into understanding.