Grafana — Monitoring Dashboards

Grafana is the standard open-source platform for building time-series monitoring dashboards. It connects to data sources — Prometheus for metrics, Loki for logs, InfluxDB for IoT and infrastructure, MySQL/PostgreSQL for application data, CloudWatch for AWS — and turns them into visual dashboards with graphs, gauges, and alerts. It's commonly used for infrastructure monitoring, application performance, home server dashboards (Pi-hole, Home Assistant stats), and business metrics.

Grafana's web interface runs on port 3000 by default. Default login is admin / admin — Grafana immediately prompts you to change this on first login.

Install Grafana

# Docker (quickest)
docker run -d \
  --name grafana \
  -p 3000:3000 \
  -v grafana_data:/var/lib/grafana \
  --restart unless-stopped \
  grafana/grafana-oss:latest

# Ubuntu
sudo apt install -y software-properties-common
wget -q -O - https://apt.grafana.com/gpg.key | sudo apt-key add -
echo "deb https://apt.grafana.com stable main" | sudo tee /etc/apt/sources.list.d/grafana.list
sudo apt update && sudo apt install grafana
sudo systemctl start grafana-server

# macOS
brew install grafana
brew services start grafana

Prometheus + Grafana (Most Common Setup)

Prometheus scrapes metrics from exporters (node_exporter for Linux system stats, cAdvisor for Docker, application-specific exporters) and stores them as time-series data. Grafana visualizes Prometheus data. The full stack as Docker Compose:

services:
  prometheus:
    image: prom/prometheus
    ports:
      - "9090:9090"
    volumes:
      - ./prometheus.yml:/etc/prometheus/prometheus.yml
      - prom_data:/prometheus

  node-exporter:
    image: prom/node-exporter
    ports:
      - "9100:9100"

  grafana:
    image: grafana/grafana-oss
    ports:
      - "3000:3000"
    volumes:
      - grafana_data:/var/lib/grafana
    environment:
      - GF_SECURITY_ADMIN_PASSWORD=yourpassword

volumes:
  prom_data:
  grafana_data:

# prometheus.yml — tell Prometheus what to scrape
global:
  scrape_interval: 15s

scrape_configs:
  - job_name: 'node'
    static_configs:
      - targets: ['node-exporter:9100']

Adding a Data Source

1. Log in at localhost:3000
2. Go to Connections → Data sources → Add new data source
3. Select your data source type (Prometheus, MySQL, InfluxDB, etc.)
4. Enter connection details (URL, credentials)
5. Click Save & test — green means connected

Pre-Built Dashboards

Grafana's dashboard library at grafana.com/grafana/dashboards has thousands of pre-built dashboards. Import one by ID:

1. Go to Dashboards → Import
2. Enter a dashboard ID (popular: 1860 for Node Exporter Full, 893 for Docker, 11835 for Home Assistant)
3. Select your Prometheus data source
4. Click Import

Alerts

Grafana alerts fire when a metric crosses a threshold. Configure in Alerting → Alert rules → New alert rule. Set conditions (e.g., CPU > 90% for 5 minutes), then configure Contact points (Slack, email, PagerDuty, webhook) in Alerting → Contact points.

Troubleshooting

Problem	Fix
localhost:3000 conflict with Node.js app	Change Grafana to another port: set http_port = 3001 in grafana.ini, or use Docker -p 3001:3000
Data source test fails	In Docker, use the service name (prometheus), not localhost, as the host in Grafana's data source URL
Dashboards show "No data"	Check the time range (top right) — default may be "Last 6 hours" but your data is older
Forgot admin password	grafana-cli admin reset-admin-password newpassword
Permission denied on volume	Grafana container runs as UID 472 — sudo chown -R 472:472 grafana_data/