3 Docker Best Practices I Learned from Carlos Nunez

I recently took the Learning Docker course on LinkedIn taught by Carlos Nunez. The course covered a wide range of topics related to Docker, including its basic concepts, networking, and Docker Compose. Along the way, I picked up some valuable best practices that I would like to share with you.

1. Use verified images for enhanced security

When using Docker, you will likely download various images from Docker Hub. While this is a flexible and easy way to work with Docker, it is also easy to download images that could be harmful to your systems or business. For example, malicious images can be used to steal credentials or launch attacks on your infrastructure.

To mitigate this risk, I recommend using Docker Hub images that are verified. Verified images have an official Docker image designation that indicates they are scanned and vetted by Docker themselves. One such image is Ubuntu, which has its designation prominently displayed on Docker Hub. However, keep in mind that there are still plenty of safe images that are not verified. To determine which images are safe, you can use image scanners like Clair, Trivy, or Dagda to inspect each layer of Docker images for potential risks.

2. Avoid using the "latest" tag

By default, Docker images have a version tag of "latest" if one is not provided after running "docker build." While this is fine for local development, it can create issues when you upload images to Docker Hub. For example, using "latest" means you won't know which version of an application you're getting when you download an image. Additionally, the version can change out from under you when you pull the image again in the future, potentially causing your application to break.

To avoid these issues, I recommend always using version tags when creating images, even for local development. This practice ensures that you can easily track which version of an image you're using and helps with rollback if needed.

3. Use non-root users for increased security

Docker containers run as the root user by default, which can make security teams nervous and leave your application vulnerable to attacks. To mitigate this risk, I recommend running containers as a user other than root. You can do this by specifying the user option when running "docker run" or "docker container create." You can use Linux user IDs or actual names for this purpose. However, be aware that some images assume that they are running as root, which can cause issues. To work around this, you might need to write additional automation to make sure your application runs correctly. For your own images, you can specify the user command within your Dockerfile to run your application as a non-root user by default.


In conclusion, Docker is a powerful tool that can help you build and deploy applications more efficiently. However, it's important to use it responsibly to ensure the security and stability of your systems. By following the best practices outlined above, you can minimize the risks associated with using Docker and ensure that your applications run smoothly.

If you're interested in learning more about Docker, I highly recommend taking the Learning Docker course by Carlos Nunez on LinkedIn. The course covers a wide range of topics and provides hands-on experience working with Docker in real-world scenarios.


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