Latest docker update causes issues on btrfs

[kernle32dll]

The commit ec709f9 did not only update docker, but enforced the overlay2 storage driver. While this is a fine default, it can actually break docker on btrfs file systems.

From the Dockerd documentation:

Note: Both overlay and overlay2 are currently unsupported on btrfs or any Copy on Write filesystem and should only be used over ext4 partitions.

Even if not breaking, its an un-intuitive change, if you don't happen to use overlay2 previously. It took me a good while to understand why all of my images and volumes were gone - which was due to the change of the storage driver.

Its easy to fix locally - just remove the storage-driver line from /etc/docker/daemon.json. But this should be removed in the package, too - IMO.

[D-Nice]

I find many issues with the change myself. The only potentially needed part there is log-driver, which should just be passed as a flag from runit, and not bog the rest of us down with some defaults we don't want AND replacing our own configs.

[kernle32dll]

Welp, the new PR now completely broke Docker for me. Daemon is not starting again anymore.

sv status docker yields:

run: docker: (pid 15449) 1s; warning: docker/log: unable to open supervise/ok: file does not exist

No clue how to fix myself.

[kernle32dll]

It is. After some tinkering I got it running again:

First, I removed the /etc/sv/docker/log folder - not sure if that did anything, but it got rid of the error message above.

Then turns out, due to the original problem I had both overlay2 and btrfs under /var/lib/docker. With the removal of the daemon.json per #19226 (edit: to be precise - I deleted it locally too after the update), Docker was unable to "guess" the correct storage driver. I deleted the overlay2 folder (warning fellow Googler, this is due to me using Btrfs, don't do that blindly), and it works again.