Collabora - Failed to get new child

I had collabora/code running fine since today, when my docker host stopped working and i had to setup a new instance. As there are no tags with the docker image: it is just the latest version as of today.
Unfortunatly I did not make a backup of the working docker image.

I changed the apache proxy setting according to the manuals and at least nextcloud and collabora seem to talk to each other. Host is running debian 8.7. Docker Version is 1.13.0 with aufs.

When looking at the logs of collabora I find:
[0:09:00.210559 [ client_ws_0006 ] WRN getNewChild: No available child. Sending spawn request to forkit and failing.| wsd/LOOLWSD.cpp:411ESC[0m
[0:09:00.210735 [ client_ws_0006 ] ERR Failed to write to pipe. Data: [spawn 1]. (errno: Broken pipe)| common/IoUtil.cpp:229ESC[0m
[0:09:05.210994 [ client_ws_0006 ] ERR Failed to get new child. Service Unavailable.| wsd/LOOLWSD.cpp:863ESC[0m
[0:09:05.211208 [ client_ws_0006 ] ERR ClientRequestHandler::handleClientRequest: WebSocketErrorMessageException: error: cmd=socket kind=serviceunavailable| wsd/LOOLWSD.cpp:1189ESC[0m
[0:09:05.211483 [ client_ws_0006 ] ERR ClientRequestHandler::handleClientRequest: exception while sending WS error message: I/O error| wsd/LOOLWSD.cpp:1

When I start a bash inside the container and do a ps with
docker exec -ti {containerid} /bin/bash I get:
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
root 1 0.0 0.0 4336 792 ? Ss+ 12:06 0:00 /bin/sh -c bash start-libreoffice.sh
root 10 0.0 0.0 20344 3172 ? S+ 12:06 0:00 bash start-libreoffice.sh
root 28 0.0 0.0 45040 2968 ? S+ 12:06 0:00 su -c /usr/bin/loolwsd --version --o:sys_template_path=/opt/lool/systemplate --o:lo_template_path=/opt/collaboraoffice5.1 –
lool 29 0.1 0.3 878172 12348 ? Ssl 12:06 0:03 /usr/bin/loolwsd --version --o:sys_template_path=/opt/lool/systemplate --o:lo_template_path=/opt/collaboraoffice5.1 --o:chil
root 1095 0.0 0.0 20532 3520 ? Ss 12:24 0:00 /bin/bash
lool 2043 78.3 0.0 0 0 ? Z 12:39 0:02 [loolforkit]
root 2049 0.0 0.0 17780 2244 ? R+ 12:39 0:00 ps -uax

Seems as if someting is wrong with the instantiation of new libreoffice instances.
Any help would be appreciated.

problem solved was debian 8.7 and CONFIG_AUFS_XATTR=n
solution: use another docker storage backend. (i.e. devicemapper)
see other posts in forum.