[Unit]
Description=Docker Application Container Engine
Documentation=https://docs.docker.com
BindsTo=containerd.service
After=network-online.target firewalld.service
Wants=network-online.target

[Service]
# Install containerd-shim-process if it's not already installed
ExecStartPre=/usr/libexec/containerd-offline-installer /var/lib/containerd-offline-installer/containerd-shim-process.tar docker.io/docker/containerd-shim-process

# 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
ExecReload=/bin/kill -s HUP $MAINPID
ExecStopPost=/usr/bin/dockerd post-stop
TimeoutSec=0
RestartSec=2
Restart=always
# On RPM Based distributions PATH isn't defined so we define it here
# /opt/containerd/bin is in front so dockerd grabs the correct runc binary
Environment="PATH=/opt/containerd/bin:/sbin:/usr/bin:/usr/local/bin:$PATH"

# 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

# Comment TasksMax if your systemd version does not supports it.
# Only systemd 226 and above support this option.
TasksMax=infinity

# 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