Скачать или смотреть How to Perform a Docker Cleanup: Managing Your /var/lib/docker Directory

Discover effective methods to manage and free up space in Docker's `/var/lib/docker/containers` directory, ensuring smoother operation of your Docker environment.
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This video is based on the question https://stackoverflow.com/q/64510352/ asked by the user 'Aswin George' ( https://stackoverflow.com/u/11339628/ ) and on the answer https://stackoverflow.com/a/64511281/ provided by the user 'davidxxx' ( https://stackoverflow.com/u/270371/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Perform a Docker Cleanup

Docker has revolutionized the way we develop applications by providing containerization capabilities that simplify code deployment and scaling. However, as containers are created and destroyed, they can accumulate a significant amount of data on your system. One common challenge Docker users face is managing disk space, especially in the /var/lib/docker/containers directory.

In this guide, we will address a common question: Can I delete old directories under /var/lib/docker/containers? We will guide you through the best practices for reclaiming space and preventing overflow in your Docker environment.

Understanding the Problem

With multiple Docker containers running, it’s easy for the /var/lib/docker/overlay2/ directory to grow significantly. In the situation presented, the user has:

16 Docker containers

Approximately 30 GB of data per directory, leading to a total of 480 GB

Increased space consumption due to multiple setups of similar directories after running docker-compose down and docker-compose up

This leads to concerns about disk space as these directories can accumulate quickly, making it critical to differentiate between necessary data and data that can be safely removed.

Can You Delete Old Directories?

Inspect Before You Delete

The first question people often ask is, "Can I just delete the old directories?" The answer is: it depends. You should take some precautions:

Inspect the Directory:

Navigate to the directory in question, e.g., /var/lib/docker/overlay2/foo123.

Check the contents and their modification dates. If these files are not recent or not associated with any running containers, they may be candidates for deletion.

Decide Whether to Delete:

If you are confident that the directory is not in use and is not critical, you can delete it using:

[[See Video to Reveal this Text or Code Snippet]]

If unsure, it’s always a good idea to create a backup before deletion:

[[See Video to Reveal this Text or Code Snippet]]

Unmount If Necessary:

If you encounter an error during deletion due to file mounting, identify the mounted files and ensure they are unmounted first to proceed with the deletion.

Reclaiming Space After docker-compose down

Immediate Reclamation Not Required

A common concern is whether you need to wait after executing docker-compose down to reclaim space. The straightforward answer is no, you don’t need to wait.

However, here are some steps you should follow:

Explicit Deletion of Containers: To free up space, you need to manually remove containers and images that aren’t in use. Use commands such as:

To remove a specific container:

[[See Video to Reveal this Text or Code Snippet]]

To perform a more comprehensive cleanup:

[[See Video to Reveal this Text or Code Snippet]]

Monitor Disk Usage Regularly: Use the command:

[[See Video to Reveal this Text or Code Snippet]]

This will help you inspect large directories within Docker regularly, allowing you to manage space proactively.

Conclusion

Managing disk space in Docker can be a challenge, especially with the /var/lib/docker/containers directory. However, by taking a careful approach to deleting old directories and understanding how to properly reclaim your disk space, you can keep your Docker environment running smoothly and efficiently.

Ensure that you always double-check before deleting any directories, and consider backing up important data to avoid unintentional loss. By following the practices outlined in this guide, you can maintain a cleaner and more efficient Docker setup.

Happy Dockering!