How to Efficiently Remove Docker Images, Containers, and Volumes?
Docker simplifies packaging your applications and services into containers, making them portable and easy to deploy. However, as you continue to use Docker, it's common to accumulate many unused images, containers, and volumes. These can clutter your environment and take up valuable disk space.
Fortunately, Docker includes various built-in tools to help you manage and clean your system directly from the command line.
In this guide, we’ll walk you through the process of how to remove Docker images, along with other unused resources like containers and volumes. By following the steps outlined, you'll learn how to clean up your Docker environment effectively, reclaim valuable disk space, and maintain an organized system.
Remove Docker Images, Containers, Volumes, and Networks? (Step-by-Step Guide)
Docker offers a single command to remove all docker images and other resources, including containers, volumes, and networks that are untagged or not linked to any container.
docker system prune
The above command cleans up unused Docker resources by removing Docker containers, dangling images, unused volumes, and networks not connected to any containers. By default, it only deletes resources that are safe to remove. Adding the --all flag enables the removal of all unused images, not just dangling ones.
To remove docker container that is not currently running and all unused images (including those that are not dangling), include the -a flag with the command.
docker system prune -a
Removing Docker Images
To remove specific images, start by using the docker images command with the -a flag. This will display all images, including intermediate layers, allowing you to identify the IDs of the images you want to delete.
docker images -a
Once you've identified the target images, use their ID or tag with the docker rmi command to remove them.
docker rmi Image Image
Remove Dangling Docker Images
Docker images are made up of several layers, and dangling images are layers that are not associated with any tagged images. These layers are unnecessary and take up disk space.
When you build an image without assigning a tag, it will show up as a dangling image since it isn't associated with any tagged image. To prevent this, always provide a tag when building an image. Alternatively, you can add a tag to an existing image later using the docker tag command.
You can find them by using the docker images command with the -f flag and setting the value to dangling=true. Once you've confirmed you want to remove them, use the docker image prune command to delete the dangling images.
docker images -f dangling=true
Now, you can remove those images using the below-given command:
docker image prune
Remove all images
You can list all Docker images on a system by using the docker images command with the -a flag.
docker images -a
Once you've decided to delete them, add the -q flag to display just the image IDs, which can then be passed to the docker rmi command for removal.
docker rmi $(docker images -a -q)
Deleting Images Based on a Specific Pattern
To remove images based on a specific pattern, you can use a combination of the docker images command and grep to filter the images.
docker images -a | grep "pattern"
Once you've identified the images, use awk to extract their IDs and pass them to the docker rmi command for deletion. Keep in mind that these utilities are not built into Docker and may not be available on all systems.
docker images -a | grep "pattern" | awk '{print $1":"$2}' | xargs docker rmiRemove Docker Containers
To remove specific containers, use the docker ps command with the -a flag to list all containers.
docker ps -a
The above command will allow you to find the names or IDs of the containers you want to delete. Now, if you want to delete a container you can delete it using this command:
docker rm ID_or_Name ID_or_Name
Remove a Container After It Exits
To automatically remove a container once it exits, you can use the docker run --rm command when creating the container. This ensures that the container is deleted as soon as it finishes running.
docker run --rm image_name
Deleting All Exited Containers
To find containers, use the docker ps -a command, which shows all containers regardless of their status: created, restarting, running, paused, or exited. To focus on exited containers, apply the -f flag and filter by status.
docker ps -a -f status=exited
Once you've confirmed the containers you want to remove, use the -q flag to get their IDs and pass them to the docker rm command for deletion.
docker rm $(docker ps -a -f status=exited -q)
Removing Containers Based on a Pattern
You can identify containers that match a specific pattern by combining the docker ps command with grep.
docker ps -a | grep "pattern”
Once you've filtered the containers you want to delete, use awk and xargs to pass their IDs to the docker rm command. Keep in mind that these utilities are not part of Docker and may not be available on all systems.
docker ps -a | grep "pattern" | awk '{print $1}' | xargs docker rmRemoving Containers Using Multiple Filters
You can apply multiple filters in Docker by using the filter flag more than once, each with a different value. This allows you to list containers that meet any of the specified conditions. For example, to remove all containers that are either in the "created" state (which can occur if a container is started with an invalid command) or have exited, you can use two separate filters.
docker ps -a -f status=exited -f status=created
To remove those containers, use this command:
docker rm $(docker ps -a -f status=exited -f status=created -q)
Stop and Delete All Containers
To view all containers on your system, use the docker ps command. By adding the -a flag, you can see all containers, including stopped ones.
docker ps -a
Once you're ready to remove them, use the -q flag to get the container IDs and pass them to the docker stop and docker rm commands to stop and delete the containers.
docker stop $(docker ps -a -q)
docker rm $(docker ps -a -q)
Remove Docker Volumes
To find the volume names you want to delete, use the docker volume ls command.
docker volume ls
After identifying the volumes, you can remove one or more of them by using the docker volume rm command.
docker volume rm volume_name volume_name
Remove Docker Container and Its Volume
When you create a container with an unnamed volume, you can remove both the container and the volume simultaneously by using the -v flag. This works only for unnamed volumes.
docker rm -v container_name
Once the container is deleted, its ID will be displayed, but there will be no direct mention of the volume removal. If the volume is unnamed, it will be quietly removed from the system. However, if it is named, the volume will remain on the system without being removed.
Removing Dangling Docker Volumes
Volumes are designed to exist independently of containers, so when a container is removed, its associated volume is not automatically deleted. If a volume is no longer attached to any containers, it becomes a dangling volume.
To identify these volumes, use the docker volume ls command with a filter to show only the dangling volumes.
docker volume ls -f dangling=true
Once you’ve confirmed the list, you can remove all of them at once using the docker volume prune command.
docker volume prune
Conclusion
This guide highlights some of the key commands for how to remove docker images, containers, and volumes. There are various other options and flags you can use with each command for different use cases. For a detailed overview, check the Docker documentation for commands like docker system prune, docker rmi, docker rm, and docker volume rm. If you have any common cleanup tasks in mind that you'd like to see covered, feel free to suggest them in the comments.
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