Grafana: What is This Monitoring Tool?
Définition
Grafana is an open-source visualisation and monitoring platform for creating interactive dashboards from multiple data sources (Prometheus, InfluxDB, Elasticsearch, PostgreSQL). It is primarily used for monitoring infrastructure metrics, application performance, and system logs in real time.What is Grafana?
Grafana is an open-source visualisation and observability platform launched in 2014 by Torkel Odegaard. It enables creating rich, interactive dashboards that aggregate data from multiple sources to offer a unified view of the state of an infrastructure, application, or business process. Grafana does not store data itself — it connects to existing sources like Prometheus, InfluxDB, Elasticsearch, PostgreSQL, MySQL, Loki, and dozens of others, then visualises them in configurable panels.
Modern observability rests on three pillars: metrics (numerical values over time, like CPU usage), logs (text events, like application errors), and traces (a request's path through microservices). Grafana unifies these three pillars in a single interface, enabling the transition from a metric alert to analysing corresponding logs in just a few clicks.
With the emergence of Grafana Cloud and the expansion of the LGTM ecosystem (Loki for logs, Grafana for visualisation, Tempo for traces, Mimir for metrics), Grafana has become much more than a simple dashboarding tool: it is a complete observability ecosystem rivalling commercial solutions like Datadog or New Relic, with the advantage of being open source.
Why Grafana Matters
Monitoring is a fundamental pillar of any production system. Without visibility into infrastructure and application state, teams operate blind and only discover problems when users report them.
- Proactive problem detection: Grafana alerts notify the team before users are impacted. An alert on disk space at 85% prevents the crash at 100%; an alert on degraded response time allows intervention before complete failure.
- Unified visibility: a single dashboard can display server metrics (CPU, memory, disk), application metrics (response time, error rate), business metrics (number of transactions, revenue), and relevant logs.
- Open source and flexible: unlike proprietary solutions (Datadog, New Relic) whose costs explode with data volume, Grafana is free and can be self-hosted. The community offers thousands of preconfigured dashboards for the most common stacks.
- DevOps culture: Grafana reinforces the culture of shared responsibility between developers and operations. When everyone can see the real-time impact of a deployment, decisions are better and problems are resolved faster.
- Multi-source: Grafana's ability to aggregate data from heterogeneous sources makes it a unique tool for complex architectures combining cloud, on-premise, and third-party services.
How It Works
Grafana functions as a visualisation layer that queries data sources in real time. A Grafana dashboard is composed of panels, each displaying a specific query to a data source. Panels can be time series graphs, gauges, tables, maps, histograms, or text.
The most common data source for infrastructure metrics is Prometheus, a monitoring system that collects metrics via HTTP scraping. Prometheus stores time series and exposes them via the PromQL query language. Grafana queries Prometheus with PromQL and displays results in interactive graphs.
For logs, Grafana integrates with Loki (the "Prometheus for logs") or Elasticsearch. Log exploration is contextual: from a graph showing a latency spike, a click switches to the logs for the corresponding period to identify the root cause.
Grafana's alert system periodically evaluates user-defined conditions (for example, "alert if the 500 error rate exceeds 1% for 5 minutes") and sends notifications via email, Slack, PagerDuty, OpsGenie, or other channels. Silences and inhibitions prevent alert storms during planned maintenance.
Concrete Example
At Kern-IT, when a Django application is deployed to production for a client, a Grafana dashboard systematically accompanies the deployment. The dashboard comprises several sections. The first displays server system metrics: CPU usage, memory, disk space, network traffic. The second shows application metrics: requests per second, average response time and percentiles (p95, p99), HTTP error rates (4xx and 5xx). The third section presents Gunicorn metrics: active workers, queued requests, and latency per endpoint.
Alerts are configured for critical thresholds: disk space below 20%, average response time above 2 seconds, 500 error rate above 0.5%. Alerts are sent to a dedicated Slack channel and by email to the technical lead. When a deployment is made via Fabric, the team monitors the dashboard in real time to verify that metrics remain stable after going live.
This proactive monitoring has enabled detecting and resolving issues before they impact users: a gradual memory leak detected by an upward trend on the memory graph, a SQL query slowdown identified through response time percentiles per endpoint.
Implementation
- Install the monitoring stack: deploy Prometheus (or an alternative) for metrics collection and Grafana for visualisation. Docker considerably simplifies this deployment.
- Configure exporters: install appropriate Prometheus exporters: node_exporter for system metrics, django-prometheus for Django metrics, and nginx-prometheus-exporter for Nginx.
- Create dashboards: start from community dashboards (grafana.com/grafana/dashboards) and adapt them to the project's specific needs. Prioritise the most critical metrics.
- Configure alerts: define alert thresholds for critical metrics and configure notification channels (Slack, email). Avoid "alert fatigue" syndrome by only alerting on what requires action.
- Document runbooks: for each alert, document the resolution procedure. When the "disk full" alert fires, what is the exact process for freeing space or increasing the disk?
- Iterate and refine: adjust alert thresholds based on operational experience. Add new panels when new metrics become relevant.
Associated Technologies and Tools
- Prometheus: monitoring and metrics collection system, the most common data source for Grafana.
- Loki: log aggregation system by Grafana Labs, the natural complement to Grafana for logs.
- Docker: simplifies deployment of the Grafana + Prometheus stack and is often the containerisation technology monitored by Grafana.
- Terraform: provisions the infrastructure that Grafana then monitors, creating a complete infrastructure management loop.
- Power BI: complementary BI tool — Grafana for real-time technical metrics, Power BI for business analysis and reporting.
- Datadog / New Relic: commercial SaaS alternatives to the Grafana/Prometheus stack, with a consumption-based pricing model.
Conclusion
Grafana has become the open-source reference for monitoring and observability. Its ability to aggregate data from multiple sources into interactive dashboards, combined with a flexible alert system, makes it an essential tool for any team operating production systems. At Kern-IT, every production deployment is accompanied by a Grafana dashboard monitoring system, application, and business metrics, ensuring problems are detected and resolved before they impact users. Monitoring is not a luxury — it is a responsibility towards the clients who rely on the reliability of our applications.
Create a deployment dashboard that the entire team checks during and after each production release. Display key metrics (response time, error rate, memory usage) with automatic annotations on each deployment. This transforms monitoring into a team reflex rather than an ops-only task.