On contint1001 Docker uses the overlay engine on the root partition (/var/lib/docker/overlay2). That should be moved to a dedicated LVS logical volume and the backend switched to devicemapper.
from docker info:
Storage Driver: overlay2 Backing Filesystem: extfs Supports d_type: true Native Overlay Diff: true
If I remember properly, we should switch to devicemapper.
We have installed Docker via the upstream Debian package 17.06.2~ce-0~debian. It seems to select overlay2 by default.