Well, first of all, I would like to say that this kind of bug is the reason many people complain and say bad thing about open source / free software. This kind of problem that sticks forever with no solution most of times brings infeasibility of use.
Anyway, I am facing this problem and I am proceeding with some investigation. I discover some things about this issue. In my case, I have a dockerfile with Wildfly image that copies a .war application and rebuilds it every deploy and the image is reloaded into docker and started again after removing the old container.
I tried the above clean up command but nothing works. In the
docker inspect command I found that section:
So, in the overlay folder you many folders with content of different containers. It seems docker keeps track of all runs of the same image:version plus the container name. Everytime I redeploy my image is with the same container name, image name and tagged version (latest), so it keeps track of the diff folder of the previous runs.
When I found the container owning the 40GB folder inside overlay, I stopped it and removed it with
docker stop and
docker rm and the folder was cleaned up to 0 bytes. I redeployed everything and the initial size was small. I discovered that it was a problem with my app that grows the log too much, but removing the container and redeploying solved the problem.
I suspect this problem is related with problems of the images, not necessarily a docker problem. Anyway, there is no easy path to find and clean this up. Let’s do some more investigation.