Serviço para Desmontar o Docker

[Unit]
Description=Clean up Docker volumes and processes
DefaultDependencies=no
Before=shutdown.target reboot.target

[Service]
Type=oneshot
ExecStart=/bin/true
ExecStop=/bin/sh /var/lock/subsys/umountdocker stop
RemainAfterExit=yes

[Install]
WantedBy=multi-user.target