Comment 2 for bug 1725230

Rebooted server but space was still low.
Rebooted with / readonly, run xfs_repair, removed anything in /lost+found (contained all the files in /var/lib/docker)
Reactivated crontab.
Status should be green again.

Investigated issue: as usual, cleanup is part of the main list of tasks, and if something goes wrong at some point in the main playbook, cleanup is not run.

Creating a fix short term, then going for the separate volume solution, that will also ease any rebuild for the server we'll need to undergo.