How to Remove Unused and Dangling Docker Images?

Introduction

Docker is a popular tool used for the containerization of applications. Docker images are the building blocks of containers. When we create a new Docker image, it gets stored in the local registry of the system. Over time, as we create and delete images, unused and dangling images start to accumulate in the system, taking up valuable disk space. In this article, we will discuss how to remove these unused and dangling Docker images.

Understanding Docker Images

Before we start cleaning up the unused and dangling Docker images, let us understand the difference between these two types of images.

Unused Docker Images

Unused Docker images refer to the images that are not associated with any containers. These images were created but never used to create a container. They can take up valuable disk space, and it is important to remove them periodically.

Dangling Docker Images

Dangling Docker images refer to the images that are not tagged and not associated with any container. They are created when we build a new image, but the previous image with the same tag was not removed. These images can also take up valuable disk space, and it is important to remove them periodically.

Removing Unused and Dangling Docker Images

To remove unused and dangling Docker images, we need to use the Docker CLI (Command Line Interface). Let us see how to remove these images step-by-step.

Step 1: List Docker Images

To list all the Docker images on your system, use the following command:

docker images

Step 2: Remove Unused Docker Images

To remove all the unused Docker images, use the following command:

docker image prune

This command will remove all the images that are not associated with any container.

Step 3: Remove Dangling Docker Images

To remove all the dangling Docker images, use the following command:

docker image prune -f

This command will remove all the images that are not tagged and not associated with any container.

Step 4: Remove Specific Docker Image

To remove a specific Docker image, use the following command:

docker image rm <IMAGE_ID>

Replace <IMAGE_ID> with the ID of the Docker image you want to remove.

Step 5: Remove All Docker Images

To remove all Docker images from your system, use the following command:

docker rmi $(docker images -aq)

This command will remove all the Docker images from your system.

Conclusion

In this article, we discussed how to remove unused and dangling Docker images from your system. It is important to periodically clean up these images to free up disk space. By following the steps mentioned in this article, you can easily remove unused and dangling Docker images.