Build a Complete Prometheus Monitoring Stack with Docker

Prometheus is a powerful monitoring tool that provides a complete solution including data collection, storage, processing, visualization, and alerting.

Key Components

Prometheus consists of four main modules: Prometheus Server, Exporter, Alertmanager, and a visualization component (Grafana).

Prometheus Server pulls metrics from Exporters, stores them, and offers the PromQL query language.

Exporter collects performance data from hosts or containers and exposes it via HTTP.

Alertmanager receives alerts from the server and dispatches notifications according to defined rules.

Visualization was originally built into Prometheus but is now commonly replaced by Grafana for richer dashboards.

Hands‑On Lab

1. Environment Setup

The lab monitors two hosts (192.168.0.101 and 192.168.0.102) and runs the following containers:

Prometheus Server (host 192.168.0.102)

Node Exporter (collects host hardware and OS metrics)

cAdvisor (collects container metrics)

Grafana (visualizes the data)

ip

Node Exporter

cAdvisor

Prometheus Server

Grafana

192.168.0.101

√

√

192.168.0.102

√

√

√

√

2. Run Node Exporter

<code>docker run -d --name node-exporter -p 9100:9100 \
 -v "/proc:/host/proc:ro" -v "/sys:/host/sys:ro" -v "/:/rootfs:ro" \
 --restart=always --net="host" \
 prom/node-exporter \
 --path.procfs /host/proc --path.sysfs /host/sys \
 --collector.filesystem.ignored-mount-points "^/(sys|proc|dev|host|etc)($|/)"</code>

Use

--net="host"

so the exporter can communicate directly with Prometheus. Access

http://<host_ip>:9100/metrics

to verify.

3. Run cAdvisor

<code>docker run -v /:/rootfs:ro -v /var/run:/var/run:rw \
 -v /sys:/sys:ro -v /var/lib/docker:/var/lib/docker:ro \
 -p 8080:8080 -t --name cadvisor --net="host" \
 google/cadvisor:latest</code>

Again

--net="host"

enables direct communication with Prometheus.

4. Run Prometheus Server

<code>docker run -d -p 9090:9090 \
 -v /root/prometheus.yml:/etc/prometheus/prometheus.yml \
 --name prometheus --net host \
 prom/prometheus</code>

The

prometheus.yml

configuration defines a global scrape interval of 15 seconds and a

static_config

that lists the exporter endpoints (e.g.,

192.168.0.101:9100

,

192.168.0.102:9100

, etc.).

Opening

http://192.168.0.102:9090

and navigating to the *Status → Targets* page shows all targets as *UP*, confirming successful data collection.

5. Install Grafana

<code>docker run -d -p 3000:3000 \
 -e "GF_SERVER_ROOT_URL=http://grafana.server.com" \
 -e "GF_SECURITY_ADMIN_PASSWORD=admin@123" \
 --net="host" grafana/grafana</code>

Access

http://192.168.0.102:3000

, add Prometheus as a data source, and import a ready‑made dashboard JSON to visualize host metrics.