Systemd service file for pt-slave-delay - https://github.com/percona/percona-toolkit

pt-slave-delay.service

[Unit]
Description = pt-slave-delay 12h delay 
After=syslog.target mysql.service
Requires=mysql.service

[Service]
Type = simple
PIDFile = /var/run/ptslavedelay.pid
ExecStartPre = /usr/bin/mysql --defaults-extra-file=/root/.my.cnf -e 'start slave; select sleep(3);'
ExecStart = /usr/bin/pt-slave-delay --daemonize --pid=/var/run/ptslavedelay.pid --nocontinue --delay 12h --defaults-file=/root/.my.cnf localhost
ExecStopPost = /usr/bin/mysql --defaults-extra-file=/root/.my.cnf -e 'stop slave;'
Restart=on-abort

[Install]
WantedBy=multi-user.target