Course

Observability 101: Metrics

A hands-on introduction to observability through metrics. Students learn the telemetry vocabulary, then build a metrics-first monitoring practice with Prometheus-compatible data, VictoriaMetrics, vmagent, MetricsQL/PromQL, Grafana, vmalert, and Alertmanager.

Observability 101: Metrics (cover image)

About This Course

Welcome to Observability 101, a hands-on course about turning production behavior into numbers you can query, graph, alert on, and trust.

Is This Course for You?

  • Is observability a new concept for you?
  • Have you heard of observability before, but not quite sure where to start?
  • Do you have metrics, but not sure what to do with them?
  • Is your monitoring setup unreliable?

If the answer to any of these questions is yes, then this course is for you.

The course aims to teach you the fundamentals of observability and fill in the gaps people often have when starting out.

The course starts with the big picture: telemetry, monitoring, observability, metrics, logs, traces, and profiles. After that, it narrows to metrics. Metrics are not the whole observability story, but they are usually the highest-value first signal: cheap to collect, compact to store, fast to query, and good enough to power most dashboards, alerts, and SLOs.

Prerequisites

Before starting, you should be comfortable with:

  • Command line: Running shell commands, using curl, and reading JSON/YAML.
  • HTTP basics: Routes, methods, status codes, and services talking over HTTP.
  • Basic math: Ratios, percentages, averages, and percentiles.

No Prometheus, VictoriaMetrics, OpenTelemetry, Kubernetes, or SRE background is assumed.

What You'll Learn

By the end of this course, you'll be able to:

  • Explain telemetry signals and choose when metrics, logs, traces, or profiles fit a question.
  • Understand what time series are and how they relate to metrics.
  • Read and design Prometheus-style metric names, labels, samples, and time series.
  • Choose counter, gauge, histogram, or summary based on what is being measured.
  • Collect metrics from various sources.
  • Query metrics with selectors, rates, aggregations, ratios, and histogram percentiles.
  • Build dashboards that answer operational questions instead of dumping graphs.
  • Instrument an application with safe metric names and labels.
  • Create alerts and basic reliability targets from metrics.
  • Protect a metrics pipeline with cardinality limits, relabeling, dropping, retention, downsampling, and deduplication.

Course Structure

The course is organized into nine modules that build on each other, followed by a capstone:

ModuleFocusLessonsStatus
1. WelcomeCore vocabulary, telemetry signals, why metrics come first, and how this course teaches2Available
2. Metrics data modelNames, labels, samples, series, cardinality, and metric types (counters, gauges, histograms, summaries)3Available
3. Collection and storageHow metrics move from process to storage: exposition format, scraping targets, pushing, vmagent, and storage with VictoriaMetrics5Coming soon
4. QueryingPromQL/MetricsQL selectors, rates, ratios, and histogram percentiles that answer operational questions5Coming soon
5. VisualizationDashboards in vmui and Grafana, and a repeatable investigation loop3Coming soon
6. Application instrumentationDeciding what your service should measure (service signals), then designing and exposing safe metrics and labels from your own code4Coming soon
7. Infrastructure monitoringThe metrics you get without writing code: host and container exporters, plus external probes of user journeys2Coming soon
8. AlertingAlerting with vmalert and Alertmanager, plus SLIs and SLOs3Coming soon
9. Pipeline reliabilityKeeping a metrics pipeline reliable: cardinality limits, relabeling, dropping, retention, downsampling, deduplication, and HA4Coming soon

Capstone: Apply What You've Learned

A single hands-on scenario that ties everything together: metrics-driven incident response, where you use what you've learned to investigate and resolve a production issue end to end. Coming soon, once the modules it draws on are in place.

Ready to start?

What's Inside?

About the Author

Márk Sági-Kazár

Márk Sági-Kazár

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