Is it safe to manually delete old Docker images? - docker

Question

I was start working on the Docker and I got some question regards on the docker images. Since each time when I create the new image and I will rmi the old images from the Docker, but looks like even after I run the commands > docker rmi 'IMAGE ID', and when I cd into the /var/lib/docker-registry/images directory, it still shows lots of images there as below:
drwxr-xr-x. 2 root root 60 May 14 13:22 65de4a13fc7cf28b4376e65efa31c5c3805e18da4eb01ad0c8b8801f4a10bc16
drwxr-xr-x. 2 root root 60 May 14 13:23 4970b995ce6435831c0e700f7c3ce6363235fbd15333af2dfb60a133ee8e9226
drwxr-xr-x. 2 root root 60 May 18 11:24 edaa232fba2214030847b7f6f57b1c05cf92a7c607332495bfab21738ceb61e1
drwxr-xr-x. 2 root root 60 May 18 16:16 09dab15bb87d1273fce7d786b2443a1d68a6cdcd397443fed4b7ac1bac298d30
drwxr-xr-x. 2 root root 60 May 18 17:20 8a622b1faf8c1df7a1f97e8fa4b841803160a800d04f6af539044f6f22ae9a38
drwxr-xr-x. 2 root root 60 May 19 14:15 b823d1a073894fdb70f7a8846f4d14eb8a2f2842f047a3d8ad847343d576c2e2
drwxr-xr-x. 2 root root 60 May 20 09:38 7c3c8e970803c9487f1f8884eb17603efb442a31b6f2082f3b26592311264e92
drwxr-xr-x. 2 root root 60 May 20 12:31 9d36120c6870e16ff7917b05bbbb84061c70e3135e40b8a10d58b1d6f50b23a3
.....
But when I run docker images command it only show:
root# docker images
REPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZE
Images1 latest f9a1d33ce592 14 hours ago 2.32 GB
Images2 latest 09dab15bb87d 9 days ago 877.2 MB
So here is my question: If something that I went wrong here since it won't delete the images folders under the /var/lib/docker-registry/images each time when I run docker rmi?
And if I can manually delete the images folders under /var/lib/docker-registry/images?
Some additional information:
I had found out under the /var/lib/docker-registry/repositories/library/ directory, there include multiple images and most of them that I already used >docker rmi to deleted, but when I cd into one of the deleted image folder, it included multiple files as:
[/var/lib/docker-registry/repositories/library/deleted-images1]
root# ls -latr
total 20
-rw-r--r--. 1 root root 159 May 27 17:39 taglatest_json
-rw-r--r--. 1 root root 64 May 27 17:39 tag_latest
-rw-r--r--. 1 root root 159 May 27 17:39 json
drwxr-xr-x. 2 root root 75 May 27 17:39 .
-rw-r--r--. 1 root root 304 May 27 17:39 _index_images
drwxr-xr-x. 14 root root 4096 May 28 10:15 ..
And in _index_images file which contain different ids as:
[{"id": "4970b995..."}, {"id": "65de4a13...."}, {"id": "f9a1d33...."}, {"id": "09dab15...."}]
So just wondering if this is caused the images folders didn't deleted from /var/lib/docker-registry/images directory when run docker rmi?
Is it safe for me to manually delete old images folders from both /var/lib/docker-registry/images and /var/lib/docker-registry/repositories/library folder?

Answer 1

When you build an image, each line of the Dockerfile creates an intermediate image or layer that is not deleted until all other images built from that layer are also deleted. You can see all of these intermediate image layers with docker images -a, and these should be the same as the contents of /var/lib/docker-registry/images. (Either way, I would strongly advise against manually deleting entries from this directory.)

Answer 2

#!/bin/bash
echo "clean containers ..."
docker ps --filter status=exited -aq | xargs --no-run-if-empty docker rm -vf
echo "clean images ..."
docker images --quiet --filter=dangling=true | xargs --no-run-if-empty docker rmi -f

Answer 3

You can try using the below command. It cleans most of the visible parts that my make your docker images list too bulky
docker images -a | grep '<none>'| awk '{print $3}' | xargs --no-run-if-empty docker rmi