Prometheus for Docker monitoring - Mini Project: Build & Apply

Prometheus for Docker monitoring

📖 Scenario: You want to monitor your Docker containers' resource usage using Prometheus. Prometheus will collect metrics from Docker containers so you can see how much CPU and memory they use.

🎯 Goal: Set up a basic Prometheus configuration to monitor Docker containers by scraping metrics from the Docker daemon's metrics endpoint.

📋 What You'll Learn

Create a Docker Compose file with Prometheus service

Add Prometheus configuration file to scrape Docker metrics

Run Prometheus container with the configuration

Verify Prometheus is scraping Docker metrics

💡 Why This Matters

🌍 Real World

Monitoring Docker containers helps keep applications healthy and performant by tracking resource usage.

💼 Career

DevOps engineers often set up Prometheus to monitor containerized applications in production environments.

1

Create Docker Compose file with Prometheus service

Create a file named docker-compose.yml with a service called prometheus using the image prom/prometheus:latest. Map port 9090 on the host to port 9090 in the container. Mount the local file prometheus.yml to /etc/prometheus/prometheus.yml inside the container as a read-only volume.

Docker

# Your code here

Need a hint?

Use the prom/prometheus:latest image and map port 9090. Mount the config file prometheus.yml as read-only.

2

Create Prometheus configuration file to scrape Docker metrics

Create a file named prometheus.yml with a scrape_configs section. Add a job named docker that scrapes metrics from http://host.docker.internal:9323/metrics every 15 seconds.

Docker

version: '3.8'
services:
  prometheus:
    image: prom/prometheus:latest
    ports:
      - "9090:9090"
    volumes:
      - ./prometheus.yml:/etc/prometheus/prometheus.yml:ro

# Your code here to create prometheus.yml with scrape_configs

Need a hint?

Use scrape_configs with a job named docker. Set scrape_interval to 15 seconds and target host.docker.internal:9323.

3

Run Prometheus container with Docker Compose

Run the command docker-compose up -d in the terminal to start the Prometheus container with the configuration.

Docker

scrape_configs:
  - job_name: 'docker'
    scrape_interval: 15s
    static_configs:
      - targets: ['host.docker.internal:9323']

# Run docker-compose up -d command

Need a hint?

Use docker-compose up -d to start Prometheus in detached mode.

4

Verify Prometheus is scraping Docker metrics

Run the command curl http://localhost:9090/metrics in the terminal and check that the output contains the string container_cpu_usage_seconds_total.

Docker

scrape_configs:
  - job_name: 'docker'
    scrape_interval: 15s
    static_configs:
      - targets: ['host.docker.internal:9323']

# Run curl command to check metrics
# Your code here

Need a hint?

Use curl http://localhost:9090/metrics and look for container_cpu_usage_seconds_total in the output.