# /etc/systemd/system/docker@.service
[Unit]
Description=Docker Application Container Engine (instance %i)
Documentation=https://docs.docker.com
After=network-online.target containerd@%i.service
Requires=containerd@%i.service
Wants=network-online.target

[Service]
Type=notify
ExecStartPre=-/sbin/ip link add name docker%i type bridge
ExecStartPre=-/sbin/ip link set docker%i up
ExecStart=/usr/bin/dockerd \
          --host=unix:///run/docker-%i.sock \
          --data-root=/var/lib/docker-%i \
          --exec-root=/run/docker-%i \
          --pidfile=/run/docker-%i.pid \
          --containerd=/run/containerd-%i/containerd.sock \
          --exec-opt native.cgroupdriver=systemd \
          --bridge=docker%i \
          --default-address-pool base=10.%i.0.0/16,size=24
ExecReload=/bin/kill -s HUP $MAINPID
LimitNOFILE=infinity
LimitNPROC=infinity
LimitCORE=infinity
TasksMax=infinity
TimeoutStartSec=0
KillMode=process
Restart=on-failure
StartLimitBurst=3
StartLimitInterval=60s

[Install]
WantedBy=multi-user.target