Reclaim Your Disk

Disk Space Consumption#

Creating images and running containers consumes disk space that later on you might want to reclaim. Here are some ways disk space is consumed unknowingly:

• Stopped containers that were not removed by using the --rm switch on the docker run command or using the docker rm command once they are stopped.

• Unused images: images that are not referenced by other images or containers.

• Dangling images: images that have no name. This happens when you docker build an image with the same tag as before, the new one replaces it and the old one becomes dangling.

• Unused volumes.

Manually removing these, one by one, can be tedious, but there are garbage collection commands that can help with that.

Reclaiming Disk Space#

Most commands ask for an interactive confirmation, but if you want to run them unattended you can add the -f switch.

Here are the commands you can run to remove the items that you don’t need:

Note that only dangling images are removed. Unused images are kept, which is fine if a network connection is scarce or unavailable because it means you keep base images that may be useful later on. If you want to remove all unused images, just use the following command:

Let’s wrap up this course with a brief introduction to orchestration in the final lesson.