Found this:
For a given service foo, the package would provide /lib/systemd/system/foo.service. You can check its status using systemctl status foo, or view its logs using journalctl -u foo. To override something in the definition of foo, do:
sudo systemctl edit foo
This creates a directory in /etc/systemd/system named after the unit, and an override.conf file in that directory (/etc/systemd/system/foo.service.d/override.conf). You can add or override settings using this file (or other .conf files in /etc/systemd/system/foo.service.d/).
Did this, but I can’t find any DOCKER_OPTS line here…
cat /lib/systemd/system/docker.service
[Unit]
Description=Docker Application Container Engine
Documentation=https://docs.docker.com
After=network.target docker.socket
Requires=docker.socket
[Service]
Type=notify
# the default is not to use systemd for cgroups because the delegate issues still
# exists and systemd currently does not support the cgroup feature set required
# for containers run by docker
ExecStart=/usr/bin/dockerd -H fd://
ExecReload=/bin/kill -s HUP $MAINPID
# Having non-zero Limit*s causes performance problems due to accounting overhead
# in the kernel. We recommend using cgroups to do container-local accounting.
LimitNOFILE=infinity
LimitNPROC=infinity
LimitCORE=infinity
# Uncomment TasksMax if your systemd version supports it.
# Only systemd 226 and above support this version.
TasksMax=infinity
TimeoutStartSec=0
# set delegate yes so that systemd does not reset the cgroups of docker containers
Delegate=yes
# kill only the docker process, not all processes in the cgroup
KillMode=process
[Install]
WantedBy=multi-user.target
This is then replaced by the file in /etc/… but I have no idea how to add DOCKER_OPTS…
So, I added
Service]
ExecStart=
ExecStart=/usr/bin/dockerd -s aufs
but this didn’t fix it. Now the error message is:
level=fatal msg="Error starting daemon: error initializing graphdriver: driver not supported"