Docker: Logging and Monitoring - Integrating with Prometheus, cAdvisor, Google Cloud Monitoring, Datadog, New Relic

1. Core Command / Concept

Integrate Docker with Prometheus for container monitoring. docker run -d --name prometheus -p 9090:9090 prometheus/prometheus

2. Step-by-Step (numbered)

1. Install Docker on your system (if not already installed). ```bash sudo apt-get update && sudo apt-get install docker.io

2. Pull the Prometheus image from Docker Hub.
   ```bash
docker pull prometheus/prometheus

1. Run Prometheus in detached mode (-d) and map port 9090. ```bash docker run -d --name prometheus -p 9090:9090 prometheus/prometheus

4. Verify Prometheus is running and listening on port 9090.
   ```bash
docker exec -it prometheus /bin/bash -c "curl http://localhost:9090"

1. Clean up by stopping and removing the Prometheus container. This deletes all stopped containers. bash docker stop prometheus && docker rm prometheus

3. Real Commands with Examples

Example 1: Running cAdvisor

• Purpose: Monitor Docker containers with cAdvisor.
• Command: docker run -d --name cadvisor -p 8080:8080 google/cadvisor
• Brief explanation of flags: -d runs the container in detached mode, -p maps port 8080 from the container to the host.

Example 2: Running Google Cloud Monitoring

• Purpose: Monitor Docker containers with Google Cloud Monitoring.
• Command: docker run -d --name gcm -p 8080:8080 google/cloud-monitoring
• Brief explanation of flags: -d runs the container in detached mode, -p maps port 8080 from the container to the host.

Example 3: Running Datadog

• Purpose: Monitor Docker containers with Datadog.
• Command: docker run -d --name datadog -p 8125:8125 datadog/docker-dd-agent
• Brief explanation of flags: -d runs the container in detached mode, -p maps port 8125 from the container to the host.

4. Common Errors (3-5)

Error 1: Prometheus not running

• Error message or symptom: Prometheus not listening on port 9090.
• Why it happens: Prometheus container not started or not running.
• One-line fix: docker start prometheus && docker exec -it prometheus /bin/bash -c "curl http://localhost:9090"

Error 2: cAdvisor not running

• Error message or symptom: cAdvisor not listening on port 8080.
• Why it happens: cAdvisor container not started or not running.
• One-line fix: docker start cadvisor && docker exec -it cadvisor /bin/bash -c "curl http://localhost:8080"

Error 3: Google Cloud Monitoring not running

• Error message or symptom: Google Cloud Monitoring not listening on port 8080.
• Why it happens: Google Cloud Monitoring container not started or not running.
• One-line fix: docker start gcm && docker exec -it gcm /bin/bash -c "curl http://localhost:8080"

5. Quick Checks (3 scenarios)

Scenario 1: Prometheus running

• Situation: Prometheus container running and listening on port 9090.
• Command: docker exec -it prometheus /bin/bash -c "curl http://localhost:9090"
• What a correct response looks like: Prometheus dashboard displayed in the browser.

Scenario 2: cAdvisor running

• Situation: cAdvisor container running and listening on port 8080.
• Command: docker exec -it cadvisor /bin/bash -c "curl http://localhost:8080"
• What a correct response looks like: cAdvisor dashboard displayed in the browser.

Scenario 3: Google Cloud Monitoring running

• Situation: Google Cloud Monitoring container running and listening on port 8080.
• Command: docker exec -it gcm /bin/bash -c "curl http://localhost:8080"
• What a correct response looks like: Google Cloud Monitoring dashboard displayed in the browser.

6. Last-Minute Reference

• Prometheus port: 9090
• cAdvisor port: 8080
• Google Cloud Monitoring port: 8080
• Datadog port: 8125
• Docker Hub: hub.docker.com
• Docker Hub image: prometheus/prometheus
• Docker Hub image: google/cadvisor
• Docker Hub image: google/cloud-monitoring
• Docker Hub image: datadog/docker-dd-agent
• Docker containers are deleted when stopped if not persisted.
• Docker images are deleted when removed if not persisted.
• Docker volumes are deleted when removed if not persisted.