Complete Docker Cleanup Guide for Cloud Servers and VPS

Why is Docker cleanup critical for cloud servers and VPS?

Regular Docker cleanup makes Prevent the root (/) partition from filling up, Improving CI/CD and Runner performance and Reduced vulnerability On cloud servers, storage costs and IOPS can increase, so freeing up disk space can be a Cost savings And it is easy to manage.

A general and safe way to clean up containers, images, and volumes

Below are step-by-step instructions with an emphasis on safety and backups. Be sure to backup and schedule maintenance before any operations in a production environment.

Main steps of cleaning

1. Review the current situation

First, check the status of Docker containers, images, volumes, and disk usage to make safer decisions.

docker ps
docker ps -a
docker images -a
docker system df
docker volume ls

2. Backup (necessary before deleting volumes)

If the volumes contain important data, be sure to back them up or use Block Storage snapshots in the provider's panel.

docker run --rm -v my_volume:/data -v $(pwd):/backup alpine tar czf /backup/my_volume_backup.tar.gz -C /data .

3. Stopping containers before deletion

Stop containers safely; use forced removal with caution if needed.

docker stop <container_id>
docker rm -f <container_id>

4. Delete containers

You can delete individual containers or all stopped containers.

docker rm <container_id>
docker container prune
# یا:
docker rm $(docker ps -a -q)

5. Delete images

Unused images or dangling Delete. Use force if needed but be careful with dependencies.

docker rmi <image_id_or_tag>
docker rmi $(docker images -a -q)
docker image prune

6. Delete volumes

Deleting volumes may destroy permanent data. Before deleting volumes, take a backup or snapshot.

docker volume rm <volume_name>
docker volume prune
docker system prune --volumes

7. Remove unnecessary networks

docker network prune

8. Delete everything to free up maximum space

If you need to reclaim as much space as possible, use the following command, but be very careful.

docker system prune -a --volumes

Practical examples and scenarios

Scenario 1 — Secure cleanup on development server (local/test)

To remove all resources built by docker-compose, use the following command.

docker-compose down --rmi all -v --remove-orphans

Explanation: –rmi all Deletes images created by Compose, -v Deletes volumes and --remove-orphans Deletes orphan containers.

Scenario 2 — GitLab CI runners and automated cleanup

It is best to perform periodic cleanup at the end of jobs or via cron so that the runners work with enough space.

docker system prune -a --volumes -f

0 3 * * * root /usr/bin/docker system prune -a --volumes -f >/dev/null 2>&1

Scenario 3 — GPU/AI server with heavy images

ML images are usually large; it is recommended to keep only the necessary versions and use snapshots for models. Also, use proper layering and cache clearing in the Dockerfile.

RUN apt-get update && apt-get install -y ... && rm -rf /var/lib/apt/lists/*

Safety tips and best practices

Here is a summary of practical tips for reducing risk and better managing storage space.

• Always back up a volume before deleting it. For databases, use mysqldump or pg_dump or snapshot.
• From commands prune Use with caution and define policies and human approval in production environments.
• Maintain consistent naming of volumes and images (e.g. project_env_service_date).
• Use labels for better management: docker ps -a --filter "label=project=myproject""
• Directory /var/lib/docker You can move it to a separate volume to make it easier to manage.
• Monitoring with tools such as cadvisor and Prometheus And setting an alert for disk full is essential.
• Security scanning of images with tools such as Claire, Trivia Or Snyk be done and vulnerable images are removed or updated.

Running a cleanup in production mode — checklist

The following checklist should be implemented in order to reduce service risk.

1. Identifying critical images and volumes
2. Backup and snapshot preparation
3. Team notification and maintenance window scheduling
4. Stop services or migrate traffic if necessary
5. Perform the deletion in order: stop and delete containers, delete redundant images, delete volumes and networks
6. Restart services and check logs
7. Post-cleanup monitoring

Useful tools and scripts

The following tools and scripts are useful in automating cleanup and security checks.

• docker-gc: General tool for garbage collection of images and containers.
• trivy / clair: For security scanning of images.
• systemd timer: To periodically run docker system prune.
• Using a bash script with logging and dry-running before actual execution.

#!/bin/bash
echo "Dry run: will remove the following images:"
docker images -f dangling=true
read -p "Proceed? y/N" ans
if [[ $ans == "y" ]]; then
  docker image prune -f
fi

Tips for Cloud Infrastructure, VPS, and Enterprise Services

On distributed servers, make sure the purge policy is applied to all nodes. For heavy workloads like rendering or AI, it is better to have separate storage (like NVMe or Block Storage) so that removing Docker does not affect data from other services.

For VPS dedicated to trading and gaming, maintaining free disk space and regular cleanup will reduce lag and improve container booting.

If you need a complex or large cleanup, seek help from the relevant team to perform operations in the maintenance window and prepare a snapshot.

Common errors and how to fix them

• Error: conflict: unable to remove repository reference because it is tagged in a local repository — Solution: Remove local tag or use docker rmi -f.
• Error: volume is in use by container — Solution: First, identify the container that is using the volume and stop/remove it: docker ps -a --filter volume=.
• Unwanted deletion of data: Solution: Regular backups and use cloud service snapshots.

Conclusion

Regular Docker cleanup is an important part of maintaining services and optimizing cost and performance. Properly implementing the steps of identifying, backing up, stopping services, and securely deleting images, containers, and volumes reduces the risk of corruption and data loss. Having a cleanup policy and automating it is especially critical in cloud and VPS environments with multiple locations.

Contact support and coordinate maintenance

If you need to do a large cleanup or set up automated scripts for GitLab CI, runners, or GPU servers, you can contact the support team to perform maintenance window operations and take snapshots.