Docker Prune: Efficient Cleanup of Unused Docker Resources
Docker is a powerful containerization platform widely used to build, run, and share applications. Over time, as you develop and deploy, Docker may accumulate unused elements such as stopped containers, dangling images, unused volumes, and inactive networks. These remnants can consume valuable disk space and negatively impact performance if not removed.
This guide shows how to use the docker prune command family to safely eliminate unused Docker resources. You’ll see the difference between docker prune and manual deletion, how each prune variant works, and best practices to avoid data loss during cleanup.
What Is docker prune?
The docker prune command family helps remove unused Docker resources including stopped containers, dangling images, unused volumes, networks, and build cache in one go. It is faster and less tedious than manual removal with docker rm or docker rmi.
| Feature | docker rm / rmi | docker prune |
|---|---|---|
| Removes one item at a time | Yes | No |
| Removes all unused resources at once | No | Yes |
| Requires specific names or IDs | Yes | No |
| Safer for manual deletions | Yes | No |
| Useful for quick cleanup | No | Yes |
Use docker rm when you need precision. Use docker prune for an efficient cleanup of everything at once.
The Short Answer Version
Below are the most common commands for removing unused Docker resources:
# Remove all unused containers, networks, images, and build cache
$ docker system prune
# Remove only stopped containers
$ docker container prune
# Remove dangling (untagged and unused) images
$ docker image prune
# Remove volumes not used by any container
$ docker volume prune
# Remove networks not connected to any container
$ docker network prune
# Remove Docker build cache
$ docker builder prune
Common Options for docker prune
Most docker prune commands support the following options:
| Option | Description |
|---|---|
| –force | Skip confirmation prompts. Use carefully to prevent unwanted deletions. |
| –filter | Filter resources by conditions such as age. Example: --filter "until=24h" removes items older than 24 hours. |
| –all | (For images) Remove all unused images, not just dangling ones. |
Using filters helps ensure that recently created resources aren’t deleted during cleanup.
Clean All Docker Resources with docker system prune
The docker system prune command removes all unused containers, networks, dangling images, and build cache.
Command Syntax
docker system prune [OPTIONS]
Command Demonstration
Interactive cleanup of unused Docker resources:
$ docker system prune
Cleanup without confirmation:
$ docker system prune --force
Cleanup of resources older than 48 hours:
$ docker system prune --filter "until=48h"
When to Use
- After intense development or frequent container changes
- When disk space becomes tight
- If no stopped containers or unused images are required
Clean Docker Containers with docker container prune
Use this command to remove only stopped containers. Running containers remain unaffected.
Command Syntax
docker container prune [OPTIONS]
Command Demonstration
Remove all stopped containers:
$ docker container prune
Remove all stopped containers without confirmation:
$ docker container prune --force
Remove stopped containers older than 24 hours:
$ docker container prune --filter "until=24h"
When to Use
- After testing or development with short-lived containers
- When stopped containers accumulate over time
- To free up disk space without touching running containers
Clean Docker Images with docker image prune
This command removes unused Docker images. By default, it deletes dangling images — those that are untagged and not referenced by containers.
Command Syntax
docker image prune [OPTIONS]
Command Demonstration
Remove all dangling images:
$ docker image prune
Remove all unused images (not only dangling ones):
$ docker image prune --all
Remove unused images older than 72 hours:
$ docker image prune --all --filter "until=72h"
When to Use
- After building or pulling multiple temporary images
- When disk space is running low due to image layers
- To remove outdated builds not linked to containers
Clean Docker Volumes with docker volume prune
This command deletes volumes not referenced by any containers. Active or attached volumes are not affected.
Command Syntax
docker volume prune [OPTIONS]
Command Demonstration
Remove all unused volumes interactively:
$ docker volume prune
Remove all unused volumes without confirmation:
$ docker volume prune --force
When to Use
- After deleting containers that used persistent volumes
- When temporary or test volumes build up
- To reclaim disk space tied to orphaned data
Warning: Volume data cannot be recovered once deleted. Always confirm which volumes are in use before pruning.
Clean Docker Networks with docker network prune
Use this command to remove Docker networks not connected to any running or stopped containers.
Command Syntax
docker network prune [OPTIONS]
Command Demonstration
Remove all unused networks interactively:
$ docker network prune
Remove all unused networks without confirmation:
$ docker network prune --force
When to Use
- After removing containers launched with
docker-compose - When testing multi-container environments
- To clean orphaned or auto-generated bridge networks
Clean Docker Build Cache with docker builder prune
This command clears the build cache created during image builds. By default, it removes only dangling (unused) cache layers.
Command Syntax
docker builder prune [OPTIONS]
Command Demonstration
Remove dangling build cache interactively:
$ docker builder prune
Remove all unused build cache without confirmation:
$ docker builder prune --all --force
When to Use
- After frequent image builds during development
- When disk space is low
- To remove intermediate cache layers no longer needed
Troubleshooting Docker Prune Issues
Cause: Docker only removes unused resources. If a container or volume is still referenced, it will not be pruned.
Solution
Stop the container:
$ docker container stop <container_id>
Remove the container:
$ docker container rm <container_id>
Run prune again:
$ docker system prune
Cause: The volume is still attached to a container.
Solution
List all volumes:
$ docker volume ls
Inspect the volume to see where it’s used:
$ docker volume inspect <volume_name>
Remove the attached container:
$ docker container rm <container_id>
Then prune volumes:
$ docker volume prune
Cause: Some resources are still referenced or not included in the last prune command.
Solution
Check disk usage summary:
$ docker system df
Run targeted prune commands:
$ docker image prune
$ docker volume prune
Run a full cleanup (if safe to do so):
$ docker system prune --all
Conclusion
In this article, you learned how to clean unused Docker resources using the docker prune command family. You explored methods for removing stopped containers, dangling images, unused volumes and networks, as well as build cache in a safe and efficient way. These commands help maintain a tidy development environment while reducing disk usage.
