[Unit]
Description=Watchtower container
Requires=network-online.target docker.service
After=docker.service

[Service]
Restart=never
ExecStartPre=-/usr/bin/docker rm -f watchtower
ExecStart=/usr/bin/docker run --name watchtower --rm  -v /var/run/docker.sock:/var/run/docker.sock -e REPO_USER=USER_NAME -e REPO_PASS=PASSWORD v2tec/watchtower:armhf-latest -i 30 --cleanup --debug
ExecStop=/usr/bin/docker stop -t 2 watchtower

[Install]
WantedBy=default.target