Introduction

This tutorial aims at providing you with the best practices for Docker troubleshooting. Docker being a popular platform used to automate the deployment, scaling, and management of applications, it's crucial to know how to efficiently solve issues and maintain the performance of your Docker containers.

By the end of this tutorial, you will learn:

• How to identify common Docker issues.
• Best practices for Docker troubleshooting.
• Docker commands for diagnosis and debugging.

Prerequisites:

• Basic understanding of Docker.
• Docker installed on your machine.

Step-by-Step Guide

Understanding Docker Logs

Docker logs are the best place to start when you're trying to troubleshoot a problem. You can access the logs of a Docker container using the docker logs command followed by the container ID or name.

docker logs [container_id]

Remember to replace [container_id] with your actual container ID.

Docker Stats

The docker stats command can provide real-time information about your Docker containers, such as CPU usage, memory usage, network I/O, disk I/O, etc.

docker stats [container_id]

Again, don't forget to replace [container_id] with your actual container ID.

Docker Events

Docker events command is used to show real-time events on the docker server. This can be especially useful in understanding what's going on behind the scenes.

docker events

Code Examples

Example 1

Let's assume you have a container that's not behaving as expected. First, we need to fetch the logs.

docker logs my_docker_container

In this example, my_docker_container is the name of the problematic container.

Example 2

If you need to monitor the CPU and memory usage of your container, use the docker stats command.

docker stats my_docker_container

This command will provide a real-time stream of data related to your container's resource usage.

Summary

In this tutorial, we've covered:

• Importance of Docker logs and how to access them.
• Usage of Docker stats for real-time container performance tracking.
• How to use Docker events to understand the Docker server's activities.

For further learning, explore more advanced Docker commands and techniques. You can refer to the official Docker documentation for more details.

Practice Exercises

1. Exercise 1: Create a Docker container and check its logs.

2. Tip: You can use any simple Docker image like hello-world for this exercise.

3. Exercise 2: Monitor the stats of your running container using the docker stats command.

4. Exercise 3: Run a faulty docker container and try to debug it using the methods discussed above.

Solutions:

1. Create a Docker container using the hello-world image.
2. Command: docker run hello-world

3. Now, check the logs using, docker logs [container_id]

4. Run the docker stats [container_id] command to monitor your container's stats.

5. If your Docker container is not starting, it could be due to many reasons. Check the Docker logs as discussed above to identify the issue.

Remember that the key to efficient troubleshooting is practice and patience.