в Ubuntu 16 или новее, вы можете использовать systemctl, а затем запускать или останавливать службы:
check process nginx with pidfile /var/run/nginx.pid
start program = "systemctl start nginx"
stop program = "systemctl stop nginx"
check process sshd with pidfile /var/run/sshd.pid
start program = "systemctl start sshd"
stop program = "systemctl stop sshd"