Monitor Mailcow With Prometheus and Grafana

Watch your Mailcow mail server's health with Prometheus and Grafana: container and host metrics, mail queue size and disk space, with alerts before users notice a problem. This is the quick overview; the full guide has every config file.

Related guide: Full Mailcow monitoring guide

1. Collect host and container metrics

Run node_exporter for the host and cAdvisor for the Docker containers on the Mailcow server, listening on localhost or a private network only.

docker run -d --name node_exporter --net=host --pid=host -v /:/host:ro,rslave quay.io/prometheus/node-exporter:latest --path.rootfs=/host

docker run -d --name cadvisor -p 8080:8080 -v /:/rootfs:ro -v /var/run:/var/run:ro -v /sys:/sys:ro -v /var/lib/docker/:/var/lib/docker:ro gcr.io/cadvisor/cadvisor:latest

2. Point Prometheus at them

Add scrape jobs to prometheus.yml on your monitoring server, then reload Prometheus.

scrape_configs:
  - job_name: mailcow-node
    static_configs:
      - targets: ['mail.example.com:9100']
  - job_name: mailcow-containers
    static_configs:
      - targets: ['mail.example.com:8080']

3. Add Grafana

Run Grafana, add Prometheus as a data source and import a Node Exporter dashboard.

docker run -d --name grafana -p 3000:3000 grafana/grafana

4. What to watch

These catch most mail outages early.

5. Set alerts

Use Grafana alerting or Alertmanager to email or message you, for example when disk use passes 85% or the mail queue keeps growing.

FAQ

Do I need to expose exporters to the internet?

No. Keep exporter ports on a private network or VPN, or allow them only from your Prometheus server's IP.

Does Mailcow have built-in monitoring?

The Mailcow UI shows container status and the mail queue, but it does not keep history or send alerts. Prometheus and Grafana add both.