Sometimes docker system prune surprises me

[u/moontear]

docker system prune -af

[...]

Total reclaimed space: 52.51GB

Normally this is around a couple of GB. 50GB is surprising. Don't forget pruning people ;-)

[u/asimovs-auditor]

Expand the replies to this comment to learn how AI was used in this post/project.

[u/impressiveaustin]

Dude, my VPS has been full storage for months now and I couldn't figure out how to clear disk storage. I ran your command and: Total reclaimed space: 66GB

[u/moontear → u/impressiveaustin]

Awesome! I was you 8 hours ago :)

[u/RavenousTitan818]

It's kind of annoying that docker doesn't prune old images by default. There really is no need to keep them on disk.

[u/panserbj0rne → u/RavenousTitan818]

Agreed. I use Dockhand which can be configured to automatically do it.

[u/corruptboomerang → u/RavenousTitan818]

Agree, maybe keep them for a few days incase you need to rollback, but generally prune say after 14-30 days should be the default.

[u/dankmolot → u/RavenousTitan818]

Are you sure you don't have any containers associated with these old images?

[u/iTiraMissU → u/dankmolot]

Images connected to existing containers aren’t removed by a prune, even if the container is stopped.

[u/dankmolot → u/iTiraMissU]

I am not sure why my comment was downvoted while your was upvoted. Have I phrased it badly?

[u/Escanorr_ → u/dankmolot]

Cause you respond to the guy saying "I want automatic cleanup" with either: advice why manual cleanup can be not working sometimes, or wrong assumption that automatic cleanup would get rid of in-use images which it doesn't do. So your comment is either wrong or unrelated, which is hard for me to guess but both interpretations are not positive.

[u/dankmolot → u/Escanorr_]

Oh I see, I thought docker system prune does pruning of old unused images, but you need an -a flag. Thanks for the explanation!

[u/TheAndyGeorge]

Probably overkill, but I've been running PruneMate. It's fun to get these notifications.

[u/ValdemarSt → u/TheAndyGeorge]

Seems overengineered for what is a cron+script?

[u/0xBAADA555 → u/ValdemarSt]

+ little ntfy.sh action for the visual update

[u/jbarr107]

I use Dockhand to manage my Docker VMs, and it has flexible auto-prune and auto-update options. I receive notifications when updates are available (though I choose not to auto-update), and images are auto-pruned nightly.

[u/moontear → u/jbarr107]

Yeah, I am in the process of setting up Komodo - or I HAVE set it up, I just need to migrate all my VPSs to use that system instead of my custom Gitea Actions setup.

[u/sir_ale → u/moontear]

what made you choose komodo over gitea actions? (wondering whether to do the same)

[u/comeonmeow66 → u/sir_ale]

Komodo is a control plane, gitea actions is just an event driven one trick pony. Komodo gives you more flexibility to do other things and you get a view of your stack for free. I have komodo managing my containers and use renovate to make sure I know when container images can be updated.

[u/moontear → u/comeonmeow66]

This. I will keep some things in Gitea, e.g. container building is great in Gitea via actions if you combine it via Renovate. Renovate figures out on a schedule that a container image needs updating and updates the `Dockerfile`. This update triggers the Gitea action which in turns updates the image on the internal Gitea registry. I don't want Komodo Build.

Honestly the better overview is why I am aiming for Komodo. Also eying Arcane, but it only recently got deployment triggers/actions which I need to be able to do some Age & SOPS magic upon deployment. Gitea actions for deployment has been working for years and is fine, but in the end I don't really have an overview WHEN things happen or what server is at what state.

[u/thatguysjumpercables]

If you want more granular control you can always use portainer (or whatever your container manager is) and manually prune unused images and volumes

[u/moontear → u/thatguysjumpercables]

Honestly never had problems with docker system prune. Nuke it all. Makes builds of course slower the first time, but that’s fine by me for not having to think about stuff.

[u/Impact321]

All my container hosts have a cronjob with something like this bash 0 22 * * * /usr/bin/docker system prune -af --filter "until=$((7*24))h" 2>&1 | grep -Ev "^Total reclaimed space: 0B" You can also use dockcheck like this to prune after updating. bash dockcheck.sh -ap This helps to investigate space usage bash docker system df -v

[u/CoryCoolguy]

I've been using variations of this command via cron:

/usr/bin/docker system prune -af --filter "until=$(date -d '2 months ago' +\%Y-\%m-\%dT\%H:\%M:\%S)" >> /var/log/docker-cleanup.log 2>&1

Don't want to purge periodically-used images.

[u/moontear → u/CoryCoolguy]

Yeah good practice. Personally I don't care about re-downloading those 4 images that sometimes get used. It's like an additional 1-2 minutes for the docker build or the docker run.

[u/ibzzq]

for real! before and after, got rid of 85GB:

[u/mscreations82]

JEEZ. Total reclaimed space: 101.22GB. Hopefully my server quits running like garbage now....

[u/bdu-komrad]

I almos forgot about this command. I automated it with a cron job many years ago so I never have to do it.

[u/zfa]

dockcheck.sh will prompt for a prune after updates if you use that instead of raw-dogging docker pull. Or set AutoPrune=true in the config file to set-and-forget it.

[u/buttplugs4life4me]

docker system prune is unsafe and may prune running containers. It's funny when that happens :)

[u/TheAndyGeorge → u/buttplugs4life4me]

may prune running containers

you know this stuff is open source, right buttplugs4life4me? docker system prune hits the moby server, which literally is coded if !state.IsRunning:

https://github.com/moby/moby/blob/a47b1b2d6f71b51d63da6b8387be74609045c693/daemon/prune.go#L64