How to Monitor Docker Containers with cAdvisor and Prometheus

How to Monitor Docker Containers with cAdvisor and Prometheus

cAdvisor (Container Advisor) collects resource usage metrics from running containers. Paired with Prometheus, it gives you comprehensive monitoring for Docker workloads on your Breeze server.

Setting Up the Monitoring Stack

Create a docker-compose.yml for the monitoring stack:

services:
  cadvisor:
    image: gcr.io/cadvisor/cadvisor:latest
    ports:
      - "8081:8080"
    volumes:
      - /:/rootfs:ro
      - /var/run:/var/run:ro
      - /sys:/sys:ro
      - /var/lib/docker/:/var/lib/docker:ro
    restart: unless-stopped

  prometheus:
    image: prom/prometheus:latest
    ports:
      - "9090:9090"
    volumes:
      - ./prometheus.yml:/etc/prometheus/prometheus.yml
      - prometheus_data:/prometheus
    restart: unless-stopped

volumes:
  prometheus_data:

Configuring Prometheus

Create prometheus.yml to scrape cAdvisor metrics:

global:
  scrape_interval: 15s

scrape_configs:
  - job_name: 'cadvisor'
    static_configs:
      - targets: ['cadvisor:8080']

  - job_name: 'prometheus'
    static_configs:
      - targets: ['localhost:9090']

Launching the Stack

docker compose up -d
# Access cAdvisor at http://your-breeze-ip:8081
# Access Prometheus at http://your-breeze-ip:9090

Useful Prometheus Queries

• container_memory_usage_bytes — memory usage per container
• rate(container_cpu_usage_seconds_total[5m]) — CPU usage rate
• container_network_receive_bytes_total — network ingress
• container_fs_usage_bytes — filesystem usage

Setting Up Alerts

Add alert rules to Prometheus for proactive monitoring:

groups:
  - name: container_alerts
    rules:
      - alert: HighMemoryUsage
        expr: container_memory_usage_bytes > 1e+09
        for: 5m
        labels:
          severity: warning
        annotations:
          summary: "Container {{ $labels.name }} using over 1GB RAM"