The docker command "docker container rm $(docker ps -aq) -f" works fine from the command line. However, when I try to run it from a makefile using the following target ("remove_all_containers")...
remove_all_containers:
docker container rm $(docker ps -aq) -f
I get the error message:
host_name$ make remove_all_containers
docker container rm -f
"docker container rm" requires at least 1 argument.
See 'docker container rm --help'.
Usage: docker container rm [OPTIONS] CONTAINER [CONTAINER...]
Remove one or more containers
make: *** [remove_all_containers] Error 1
Clearly, when executed from within the makefile, the "docker ps" command is not being properly being properly executed in a way where its results can be collected and passed into the "container rm" command.
My Question: How do I get the "docker ps" command to run correctly from within the makefile and pass its results correctly into the "docker rm" command, also within the makefile?
Thanks, in advance, for any assistance you can offer.
You need a second $ in your recipe:
remove_all_containers:
docker container rm $$(docker ps -aq) -f
# ^
The single $ is expanded as a makefile variable when the makefile is parsed. It expands to blank. Make therefore passes docker container rm -f to your shell. The second $ sign causes make to expand $$ to $, and it will pass docker container rm $(docker ps -aq) -f to bash, which I'm guessing is what you want.
Notice, if you put the shell in there as #EricMd proposed, it will run a shell command, but that command will be run at Makefile read time, as opposed to the time that the recipe is executed. If the docker ps -aq command is dependent on any other artifacts of your build it would not work.
Sounds like you don't have any containers in docker to remove. I sometimes use a different syntax for this scenario:
remove_all_containers:
docker container ls -aq | xargs --no-run-if-empty docker container rm -f
The xargs syntax will not run docker container rm if there are no containers to delete.
According to the documentation, docker ps -a should list all containers.
You obtained this message "docker container rm" requires at least 1 argument certainly because you forgot to prepend the command at stake with Make's shell builtin:
remove_all_containers:
docker container rm $(shell docker ps -aq) -f
Note also that the docker ps admits a filtering feature: the online doc describes the various flavors of the corresponding -f flag.
For example, below are three Bash alias examples that can be useful to (i) stop all containers, (ii) remove all stopped containers; and (iii) remove dangling images−that would be tagged as <none> when doing docker images ls:
alias docker-stop='docker stop $(docker ps -a -q)'
alias docker-clean='docker rm $(docker ps -a -q -f status=exited)'
alias docker-purge='docker rmi $(docker images -q -f dangling=true)'
I tested for 2 way follow bellow answer:
remove_all_containers:
docker container rm $$(docker ps -aq) -f
remove_all_containers:
docker container rm $(shell docker ps -aq) -f
Is there any command which can combine the docker stop and docker rm command together ? Each time I want to delete a running container, I need to execute 2 commands sequentially, I wonder if there is a combined command can simplify this process.
docker stop CONTAINER_ID
docker rm CONTATINER_ID
You can use :
docker rm -f CONTAINER_ID
It will remove the container even if it is still running.
https://docs.docker.com/engine/reference/commandline/rm/
You can also run your containers with --rm option (e.g. docker run --rm -it alpine), it will be automatically removed when stopped.
https://docs.docker.com/engine/reference/run/#clean-up---rm
Edit: The rm -f might be dangerous for your data and is best suited for test or development containers. #Bernard's comment on this subject is worth reading.
docker stop CONTAINER_ID | xargs docker rm
You can stop and remove the container with a single command the $_ gives you the last echo
docker stop CONTAINER && docker rm $_
In my case, to remove the running containers I used
docker rm -f $(docker ps -a -q)
In case you also need to remove the images, then run
docker rmi $(docker images -q) afterwards.
Only run docker rmi $(docker images -q) if you want to remove the images.
https://www.ctl.io/developers/blog/post/gracefully-stopping-docker-containers/
You can use kill, and also by using rm and the force flag it will also use kill.
Remove all containers: docker ps -aq | xargs docker rm -f
This will stop and remove all images including running containers as we are using -f
docker rmi -f $(docker images -a -q)
Use the docker ps command with the -a flag to locate the name or ID of the containers you want to remove
docker ps -a
To remove: $ docker rm ID_or_Name ID_or_Name
Remove a container upon exit:
If you know when you’re creating a container that you won’t want to keep it around once you’re done, you can run docker run --rm to automatically delete it when it exits.
Run and Remove : docker run --rm image_name
Remove all exited containers:
You can locate containers using docker ps -a and filter them by their status: created, restarting, running, paused, or exited. To review the list of exited containers, use the -f flag to filter based on status. When you've verified you want to remove those containers, using -q to pass the IDs to the docker rm command.
List:
docker ps -a -f status=exited
docker rm $(docker ps -a -f status=exited -q)
Remove containers using more than one filter:
Docker filters can be combined by repeating the filter flag with an additional value. This results in a list of containers that meet either condition. For example, if you want to delete all containers marked as either Created (a state which can result when you run a container with an invalid command) or Exited, you can use two filters:
docker ps -a -f status=exited -f status=created
Stop and Remove all the containers:
docker stop $(docker ps -a -q)
docker rm $(docker ps -a -q)
For removing a single container
docker rm -f CONTAINER_ID
For removing all containers
docker rm -f `docker container ps -qa`
To remove all stopped containers docker system prune
To stop live container, docker stop CONTAINER_ID waits 10 sec and it calls docker kill CONTAINER_ID
Or with docker kill CONTAINER_ID, you can immediately stop the container
remove all container with xargs
docker ps -a -q | xargs docker rm
for stop all
sudo docker ps -a -q |sudo xargs docker stop
remove single container
docker rm -f <container_id>
When running Docker for a long time, there are a lot of images in system. How can I remove all unused Docker images at once safety to free up the storage?
In addition, I also want to remove images pulled months ago, which have the correct TAG.
So, I'm not asking for removing untagged images only. I'm searching for a way to remove general unused images, which includes both untagged and other images such as pulled months ago with correct TAG.
(original answer see below)
Update Sept. 2016: Docker 1.13: PR 26108 and commit 86de7c0 introduce a few new commands to help facilitate visualizing how much space the docker daemon data is taking on disk and allowing for easily cleaning up "unneeded" excess.
docker system prune will delete ALL dangling data (i.e. In order: containers stopped, volumes without containers and images with no containers). Even unused data, with -a option.
You also have:
docker container prune
docker image prune
docker network prune
docker volume prune
For unused images, use docker image prune -a (for removing dangling and ununsed images).
Warning: 'unused' means "images not referenced by any container": be careful before using -a.
As illustrated in A L's answer, docker system prune --all will remove all unused images not just dangling ones... which can be a bit too much.
Combining docker xxx prune with the --filter option can be a great way to limit the pruning (docker SDK API 1.28 minimum, so docker 17.04+)
The currently supported filters are:
until (<timestamp>) - only remove containers, images, and networks created before given timestamp
label (label=<key>, label=<key>=<value>, label!=<key>, or label!=<key>=<value>) - only remove containers, images, networks, and volumes with (or without, in case label!=... is used) the specified labels.
See "Prune images" for an example.
Warning: there is no "preview" or "--dry-run" option for those docker xxx prune commands.
This is requested with moby/moby issue 30623 since 2017, but seems tricky to be implemented (Aug. 2022)
Having a more representative overview of what will be pruned will be quite complicated, for various reasons;
race conditions (can be resolved by documenting the limitations);
A container/image/volume/network may not be in use at the time that "dry run" is used, but may be in use the moment the actual prune is executed (or vice-versa), so dry run will always be an "approximation" of what will be pruned.
the more difficult part is due to how objects (containers, images, networks etc.) depend on each other.
For example, an image can be deleted if it no longer has references to it (no more tags, no more containers using it); this is the reason that docker system prune deletes objects in a specific order (first remove all unused containers, then remove unused images).
In order to replicate the same flow for "dry-run", it will be needed to temporarily construct representation of all objects and where they're referenced based on that (basically; duplicate all reference-counters, and then remove references from that "shadow" representation).
Finally; with the work being done on integrating the containerd snapshotter (image and layer store), things may change more;
For example, images can now be multi-arch, and (to be discussed), "pruning" could remove unused variants (architectures) from an image to clean up space, which brings another dimension to calculating "what can be removed".
Original answer (Sep. 2016)
I usually do:
docker rmi $(docker images --filter "dangling=true" -q --no-trunc)
I have an [alias for removing those dangling images: drmi]13
The dangling=true filter finds unused images
That way, any intermediate image no longer referenced by a labelled image is removed.
I do the same first for exited processes (containers)
alias drmae='docker rm $(docker ps -qa --no-trunc --filter "status=exited")'
As haridsv points out in the comments:
Technically, you should first clean up containers before cleaning up images, as this will catch more dangling images and less errors.
Jess Frazelle (jfrazelle) has the bashrc function:
dcleanup(){
docker rm -v $(docker ps --filter status=exited -q 2>/dev/null) 2>/dev/null
docker rmi $(docker images --filter dangling=true -q 2>/dev/null) 2>/dev/null
}
To remove old images, and not just "unreferenced-dangling" images, you can consider docker-gc:
A simple Docker container and image garbage collection script.
Containers that exited more than an hour ago are removed.
Images that don't belong to any remaining container after that are removed.
Update the second (2017-07-08)
Refer (again) to VonC, using the even more recent system prune. The impatient can skip the prompt with the -f, --force option:
docker system prune -f
The impatient and reckless can additionally remove "unused images not just the dangling ones" with the -a, --all option:
docker system prune -af
https://docs.docker.com/engine/reference/commandline/system_prune/
Update
Refer to VonC's answer which uses the recently added prune commands. Here is the corresponding shell alias convenience:
alias docker-clean=' \
docker container prune -f ; \
docker image prune -f ; \
docker network prune -f ; \
docker volume prune -f '
Old answer
Delete stopped (exited) containers:
$ docker ps --no-trunc -aqf "status=exited" | xargs docker rm
Delete unused (dangling) images:
$ docker images --no-trunc -aqf "dangling=true" | xargs docker rmi
If you have exercised extreme caution with regard to irrevocable data loss, then you can delete unused (dangling) volumes (v1.9 and up):
$ docker volume ls -qf "dangling=true" | xargs docker volume rm
Here they are in a convenient shell alias:
alias docker-clean=' \
docker ps --no-trunc -aqf "status=exited" | xargs docker rm ; \
docker images --no-trunc -aqf "dangling=true" | xargs docker rmi ; \
docker volume ls -qf "dangling=true" | xargs docker volume rm'
References
docker ps -f
docker rm
docker images -f
docker rmi
Docker v1.9.0 release notes
docker volume ls
docker volume rm
The other answers are great, specifically:
docker system prune # doesn't clean out old images
docker system prune --all # cleans out too much
But I needed something in the middle of the two commands so the filter option was what I needed:
docker image prune --all --filter "until=4320h" # delete images older than 6 months ago; 4320h = 24 hour/day * 30 days/month * 6 months
For reference: https://docs.docker.com/config/pruning/#prune-images
To remove old tagged images that are more than a month old:
$ docker images --no-trunc --format '{{.ID}} {{.CreatedSince}}' \
| grep ' months' | awk '{ print $1 }' \
| xargs --no-run-if-empty docker rmi
Note that it'll fail to remove images that are used by a container, referenced in a repository, has dependent child images... which is probably what you want. Else just add -f flag.
Example of /etc/cron.daily/docker-gc script:
#!/bin/sh -e
# Delete all stopped containers (including data-only containers).
docker ps -a -q --no-trunc --filter "status=exited" | xargs --no-run-if-empty docker rm -v
# Delete all tagged images more than a month old
# (will fail to remove images still used).
docker images --no-trunc --format '{{.ID}} {{.CreatedSince}}' | grep ' months' | awk '{ print $1 }' | xargs --no-run-if-empty docker rmi || true
# Delete all 'untagged/dangling' (<none>) images
# Those are used for Docker caching mechanism.
docker images -q --no-trunc --filter dangling=true | xargs --no-run-if-empty docker rmi
# Delete all dangling volumes.
docker volume ls -qf dangling=true | xargs --no-run-if-empty docker volume rm
According to the doc, the following command will delete images older than 48 hours.
$ docker image prune --all --filter until=48h
Assuming you have Docker 1.13 or higher you can just use the prune commands. For your question specifically for removing old images, you want the first one.
# Remove unused images
docker image prune
# Remove stopped containers.
docker container prune
# Remove unused volumes
docker volume prune
# Remove unused networks
docker network prune
# Command to run all prunes:
docker system prune
I would recommend not getting used to using the docker system prune command. I reckon users will accidentally remove things they don't mean to. Personally, I'm going to mainly be using the docker image prune and docker container prune commands.
Until now (Docker version 1.12) we are using the following command to delete all the running containers. Also, if we want to delete the volumes, we can do that manually using its respective tag -v in the following command.
Delete all Exited Containers
docker rm $(docker ps -q -f status=exited)
Delete all Stopped Containers
docker rm $(docker ps -a -q)
Delete All Running and Stopped Containers
docker stop $(docker ps -a -q)
docker rm $(docker ps -a -q)
Remove all containers, without any criteria
docker container rm $(docker container ps -aq)
But, in version 1.13 and above, for complete system and cleanup, we can directly user the following command:
docker system prune
All unused containers, images, networks and volumes will get deleted. We can also do this using the following commands that clean up the individual components:
docker container prune
docker image prune
docker network prune
docker volume prune
This worked for me:
docker rmi $(docker images | grep "^<none>" | awk "{print $3}")
I recently wrote a script to solve this on one of my servers:
#!/bin/bash
# Remove all the dangling images
DANGLING_IMAGES=$(docker images -qf "dangling=true")
if [[ -n $DANGLING_IMAGES ]]; then
docker rmi "$DANGLING_IMAGES"
fi
# Get all the images currently in use
USED_IMAGES=($( \
docker ps -a --format '{{.Image}}' | \
sort -u | \
uniq | \
awk -F ':' '$2{print $1":"$2}!$2{print $1":latest"}' \
))
# Get all the images currently available
ALL_IMAGES=($( \
docker images --format '{{.Repository}}:{{.Tag}}' | \
sort -u \
))
# Remove the unused images
for i in "${ALL_IMAGES[#]}"; do
UNUSED=true
for j in "${USED_IMAGES[#]}"; do
if [[ "$i" == "$j" ]]; then
UNUSED=false
fi
done
if [[ "$UNUSED" == true ]]; then
docker rmi "$i"
fi
done
Here is a script to clean up Docker images and reclaim the space.
#!/bin/bash -x
## Removing stopped container
docker ps -a | grep Exited | awk '{print $1}' | xargs docker rm
## If you do not want to remove all container you can have filter for days and weeks old like below
#docker ps -a | grep Exited | grep "days ago" | awk '{print $1}' | xargs docker rm
#docker ps -a | grep Exited | grep "weeks ago" | awk '{print $1}' | xargs docker rm
## Removing Dangling images
## There are the layers images which are being created during building a Docker image. This is a great way to recover the spaces used by old and unused layers.
docker rmi $(docker images -f "dangling=true" -q)
## Removing images of perticular pattern For example
## Here I am removing images which has a SNAPSHOT with it.
docker rmi $(docker images | grep SNAPSHOT | awk '{print $3}')
## Removing weeks old images
docker images | grep "weeks ago" | awk '{print $3}' | xargs docker rmi
## Similarly you can remove days, months old images too.
Original script
https://github.com/vishalvsh1/docker-image-cleanup
Usually Docker keeps all temporary files related to image building and layers at
/var/lib/docker
This path is local to the system, usually at THE root partition, "/".
You can mount a bigger disk space and move the content of /var/lib/docker to the new mount location and make a symbolic link.
This way, even if Docker images occupy space, it will not affect your system as it will be using some other mount location.
Original post: Manage Docker images on local disk
I'm using this command:
export BEFORE_DATETIME=$(date --date='10 weeks ago' +"%Y-%m-%dT%H:%M:%S.%NZ")
docker images -q | while read IMAGE_ID; do
export IMAGE_CTIME=$(docker inspect --format='{{.Created}}' --type=image ${IMAGE_ID})
if [[ "${BEFORE_DATETIME}" > "${IMAGE_CTIME}" ]]; then
echo "Removing ${IMAGE_ID}, ${BEFORE_DATETIME} is earlier then ${IMAGE_CTIME}"
docker rmi -f ${IMAGE_ID};
fi;
done
This will remove all images whose creation time is greater than 10 weeks ago.
If you want to remove images pulled X months ago, you can try the below example which remove images created three months ago:
three_months_old_images=`docker images | grep -vi "<none>" | tr -s ' ' | cut -d" " -f3,4,5,6 | grep "3 months ago" | cut -d" " -f1`
docker rmi $three_months_old_images
To prune all images and volumes as well
docker system prune -af --volumes
docker system prune -a
(You'll be asked to confirm the command. Use -f to force run, if you know what you're doing.)
#VonC already gave a very nice answer, but for completeness here is a little script I have been using---and which also nukes any errand Docker processes should you have some:
#!/bin/bash
imgs=$(docker images | awk '/<none>/ { print $3 }')
if [ "${imgs}" != "" ]; then
echo docker rmi ${imgs}
docker rmi ${imgs}
else
echo "No images to remove"
fi
procs=$(docker ps -a -q --no-trunc)
if [ "${procs}" != "" ]; then
echo docker rm ${procs}
docker rm ${procs}
else
echo "No processes to purge"
fi
To remove tagged images which have not container running, you will have to use a little script:
#!/bin/bash
# remove not running containers
docker rm $(docker ps -f "status=exited" -q)
declare -A used_images
# collect images which has running container
for image in $(docker ps | awk 'NR>1 {print $2;}'); do
id=$(docker inspect --format="{{.Id}}" $image);
used_images[$id]=$image;
done
# loop over images, delete those without a container
for id in $(docker images --no-trunc -q); do
if [ -z ${used_images[$id]} ]; then
echo "images is NOT in use: $id"
docker rmi $id
else
echo "images is in use: ${used_images[$id]}"
fi
done
Remove old containers weeks ago.
docker rm $(docker ps -a | grep "weeks" | awk '{ print $1; }')
Remove old images weeks ago. Be careful. This will remove base images which was created weeks ago but which your new images might be using.
docker rmi $(docker images | grep 'weeks' | awk '{ print $3; }')
How to remove a tagged image
docker rmi the tag first
docker rmi the image.
# that can be done in one docker rmi call e.g.: #
docker rmi <repo:tag> <imageid>
(this works Nov 2016, Docker version 1.12.2)
e.g.
$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
usrxx/the-application 16112805 011fd5bf45a2 12 hours ago 5.753 GB
usryy/the-application vx.xx.xx 5af809583b9c 3 days ago 5.743 GB
usrzz/the-application vx.xx.xx eef00ce9b81f 10 days ago 5.747 GB
usrAA/the-application vx.xx.xx 422ba91c71bb 3 weeks ago 5.722 GB
usrBB/the-application v1.00.18 a877aec95006 3 months ago 5.589 GB
$ docker rmi usrxx/the-application:16112805 && docker rmi 011fd5bf45a2
$ docker rmi usryy/the-application:vx.xx.xx && docker rmi 5af809583b9c
$ docker rmi usrzz/the-application:vx.xx.xx eef00ce9b81f
$ docker rmi usrAA/the-application:vx.xx.xx 422ba91c71bb
$ docker rmi usrBB/the-application:v1.00.18 a877aec95006
e.g. Scripted remove anything older than 2 weeks.
IMAGESINFO=$(docker images --no-trunc --format '{{.ID}} {{.Repository}} {{.Tag}} {{.CreatedSince}}' |grep -E " (weeks|months|years)")
TAGS=$(echo "$IMAGESINFO" | awk '{ print $2 ":" $3 }' )
IDS=$(echo "$IMAGESINFO" | awk '{ print $1 }' )
echo remove old images TAGS=$TAGS IDS=$IDS
for t in $TAGS; do docker rmi $t; done
for i in $IDS; do docker rmi $i; done
docker rm $(docker ps -faq)
docker rmi $(docker ps -faq)
-f force
-a all
-q in the mode
First, run docker images to see list of images and copy IMAGE HASH ID into clipboard.
Run docker rmi -f <Image>
Remember option -f is force deleting.
Occasionally I have run into issues where Docker will allocate and continue to use disk space, even when the space is not allocated to any particular image or existing container. The latest way I generated this issue accidentally was using "docker-engine" centos build instead of "docker" in RHEL 7.1. What seems to happen is sometimes the container clean-ups are not completed successfully and then the space is never reused. When the 80GB drive I allocated as / was filled with /var/lib/docker files I had to come up with a creative way to resolve the issue.
Here is what I came up with. First to resolve the disk full error:
Stop docker: systemctl stop docker
Allocated a new drive mounted as say /mnt/docker .
Move all the files in /var/lib/docker to /mnt/docker . I used the command:
rsync -aPHSx --remove-source-files /var/lib/docker/ /mnt/docker/
Mount the new drive to /var/lib/docker.
At this point I no longer had a disk full error, but I was still wasting a huge amount of space. The next steps are to take care of that.
Start Docker: systemctl start docker
Save the all the images:
docker save $(docker images |sed -e '/^<none>/d' -e '/^REPOSITORY/d' -e 's,[ ][ ]*,:,' -e 's,[ ].*,,') > /root/docker.img
Uninstall docker.
Erase everything in /var/lib/docker:
rm -rf /var/lib/docker/[cdintv]*
Reinstall docker
Enable docker: systemctl enable docker
Start docker: systemctl start docker
Restore images:
docker load < /root/docker.img
Start any persistent containers you need running.
This dropped my disk usage from 67 GB for docker to 6 GB for docker.
I do not recommend this for everyday use. But it is useful to run when it looks like docker has lost track of used disk space do to software errors, or unexpected reboots.
docker rm `docker ps -aq`
or
docker rm $(docker ps -q -f status=exited)
If you wish to automatically/periodically clean up exited containers and remove images and volumes that aren't in use by a running container you can download the image meltwater/docker-cleanup.
Just run:
docker run -d -v /var/run/docker.sock:/var/run/docker.sock:rw -v /var/lib/docker:/var/lib/docker:rw --restart=unless-stopped meltwater/docker-cleanup:latest
It runs every 30 minutes by default. You can however set the delay time by using this flag in seconds (DELAY_TIME=1800 option).
More details: https://github.com/meltwater/docker-cleanup/blob/master/README.md
If you build these pruned images yourself (from some other, older base images) please be careful with the accepted solutions above based on docker image prune, as the command is blunt and will try to remove also all dependencies required by your latest images (the command should be probably renamed to docker image*s* prune).
The solution I came up for my docker image build pipelines (where there are daily builds and tags=dates are in the YYYYMMDD format) is this:
# carefully narrow down the image to be deleted (to avoid removing useful static stuff like base images)
my_deleted_image=mirekphd/ml-cpu-py37-vsc-cust
# define the monitored image (tested for obsolescence), which will be usually the same as deleted one, unless deleting some very infrequently built image which requires a separate "clock"
monitored_image=mirekphd/ml-cache
# calculate the oldest acceptable tag (date)
date_week_ago=$(date -d "last week" '+%Y%m%d')
# get the IDs of obsolete tags of our deleted image
# note we use monitored_image to test for obsolescence
my_deleted_image_obsolete_tag_ids=$(docker images --filter="before=$monitored_image:$date_week_ago" | grep $my_deleted_image | awk '{print $3}')
# remove the obsolete tags of the deleted image
# (note it typically has to be forced using -f switch)
docker rmi -f $my_deleted_image_obsolete_tag_ids
See the official reference for docker system prune
docker system prune will remove:
all stopped containers
all networks not used by at least one container
all dangling images
all build cache
docker system prune -a will do the same, but in additional to removing all dangling images, it will more broadly remove:
all images without at least one container associated to them
What are dangling images?
Docker images consist of multiple layers that get wrapped inside a parent 'container layer' when the overall container image is generated from a Dockerfile. Dangling images are layers that have no relationship to any other tagged images, and will therefore never have any use within any new containers that are built. They no longer serve a purpose and consume disk space.
For example a dangling image can be created by the following process:
Build a named image my-image from Dockerfile, without specifying any tag:
FROM ubuntu:latest
CMD ["echo", "Hello World"]
docker build -t my-image
docker images
REPOSITORY TAG IMAGE ID
my-image latest 7ed6e7202eca <--- created, not dangling
ubuntu latest 825d55fb6340
Update the Dockerfile:
FROM ubuntu:latest
CMD ["echo", "Hello, World!"]
Rebuild image re-using the previous name, without specifying any tag:
docker build -t my-image
docker images
REPOSITORY TAG IMAGE ID
my-image latest da6e74196f66 <--- replacement layer
<none> <none> 7ed6e7202eca <--- previous layer, now dangling
ubuntu latest 825d55fb6340
The build created a new my-image layer. As we can see, the layer that was originally created is still there, but its name and tag are set to <none>:<none>. It will never be possible for this layer to be associated with any docker container layer, which means it's 'dangling'
What are images without at least one container associated to them?
An unused image means that it has not been assigned or used in a container. For example, docker ps -a will list all of your running and stopped containers. Any image being used by any of these containers is a "used image".
When running docker system prune -a, it will remove both unused and dangling images. Any image with at least one container associated to it will not be affected.
There is sparrow plugin docker-remove-dangling-images you can use to clean up stopped containers and unused (dangling) images:
$ sparrow plg run docker-remove-dangling-images
It works both for Linux and Windows OS.
If you have a lot of them, it can be really tedious to remove them, but lucky for us Docker has a few commands to help us eliminate dangling images. In older versions of Docker (and this still works today), you can delete dangling images on their own by running docker rmi -f $(docker images -f "dangling=true" -q) .
I usually do docker rm -f $(docker ps -a -q) and docker system prune to purge all dangling containers.
The below command will help to remove all unused and old images from local repository
==> docker system prune --all
What is the Docker way to clean up all stopped Docker containers but retain data-only containers?
docker rm $(docker ps -qa -f status=exited) removes these too!
How to clean up the according images?
In general there is no definitive way to distinguish data-only from other containers. If you wish them to survive your cleansing, you could probably design a certain name scheme and have more elaborate scripts that wouldn't remote containers with name, say, starting with data-.
Following Mykolas proposal I introduced a naming convention requiring all data-only containers to be suffixed by -data.
To remove all stopped containers, except those named *-data:
docker ps -a -f status=exited | grep -v '\-data *$'| awk '{if(NR>1) print $1}' | xargs -r docker rm
To remove all unused images afterwards:
docker rmi $(docker images -qa -f dangling=true)
(the images used by the data-only containers are retained)
May be you can, in the docker run command of all your data-only container add a -e "type=data-only", and then filter based on this criteria, either with a grep or with a docker inspect example, I start a container with sudo docker run -it -e type=data-only ubuntu bash
root#f7e9ea4efbd9:/# and then sudo docker inspect -f "{{ .Config.Env }}" f7e shows
[type=data-only PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin]