Document how to cleanup images to free disk space

[mattfarina]

When working with a lot of images it's not uncommon to run into disk space issues in the VM. Document how one can clean this up. There are a few methods including...

1. Wiping all container images with the click of a button in the settings
2. Using the UI to bulk delete images
3. Using the CLI to delete images

[mattfarina]

This could be a tutorial

[aminmkhan]

I think for dockerd (moby) the steps are fairly well documented, for instance in this tutorial.

Rancher Desktop has a Factory Reset option, but this also deletes the Lima VM, but there could be an option in UI to just also remove all existing images and containers.

I think this issue can be closed.

[Enalmada]

My disk just filled up while I was working on a Dockerfile and generating a ton of build cache without realizing it. Despite going through all the docker cleaning and pruning motions I could find, it didn't help. Turns out rancher-desktop was holding 85 gigs of my disk up with empty space?

It would be great if people didn't have to do a Factory Reset to free it.

[fingers10]

@Enalmada Thanks for the inputs. I was wondering where all the space getting consumed. Now I found it.

[aj-scram]

@Enalmada holy hell I was wondering about this myself

[edrandall]

Suffering this same issue rn after a heavy docker build session.
docker images shows only 4 small images, docker container ls -a shows no stopped containers, and yet, within the VM /var/lib/docker/overlay2 is holding on to 88Gb.

Answer seems to be docker system prune which deleted some 80Gb of build cache objects.

Update: docker builder du and docker builder prune are what's required here.

[cwhsu1984]

Suffering this same issue rn after a heavy docker build session. docker images shows only 4 small images, docker container ls -a shows no stopped containers, and yet, within the VM /var/lib/docker/overlay2 is holding on to 88Gb.

Answer seems to be docker system prune which deleted some 80Gb of build cache objects.

Update: docker builder du and docker builder prune are what's required here.

I'll try this next time. It's insane to get your C disk left with 200MB, and a factory reset to rancher desktop gives you back 50GB...
There should be a one-click function or documentation somewhere that helps user solve this issues.

[edrandall]

In the UI, look in Extensions and install the Disk Usage extension, this shows the same as docker system df on the cli.
There's also a one-click Reclaim space button

[cmahnke]

@edrandall: This issue seems to be Lima specific: Your proposal doesn't work to /lima/0/diffdisk (on OS X).
The extension you mentioned works on the Docker level, the issue is the volume of the included VM itself...

[edrandall]

@cmahnke I'm not sure I understand what you're saying. Please expand/explain what you're seeing.
The title of this issue is "how to cleanup images to free space" and the extension and docker [system|builder|image] prune commands both achieve that. I'm also using OSX.

[cmahnke]

@edrandall: Ok, maybe I have confused the issues / discussions...
#2871

There seem to be a regression.

[arcaartem]

Dropping a note here for my future self, in case I forget:

After you run docker [system|builder|image] prune commands, make sure to exit Rancher Desktop completely, because while the images will be cleared from the VM, the actual disk space won't be claimed back until you exit from the app (because the code that actually claims the disk space runs on startup and on exit)

[jandubois]

@arcaartem You can also run the fstrim command explicitly without exiting Rancher Desktop:

$ rdctl shell sudo fstrim /mnt/data

[cmahnke]

$ rdctl shell sudo fstrim /mnt/data

How about adding this to to the Rancher GUI? Either direct or via a Extension / Plugin?

[jandubois]

How about adding this to to the Rancher GUI? Either direct or via a Extension / Plugin?

It would be nice if we could automatically run it after you press Reclaim space in the "Disk Usage" extension, but that one comes from Docker and is built for Docker Desktop. Maybe via some kind of Greasemonkey/userscript style code injection.