[Unit]
Description=AI Rpc Server
After=network.target
After=syslog.target

[Service]
Type=simple
LimitNOFILE=65535
ExecStart=/usr/bin/php {your server path}
ExecReload=/bin/kill -USR1 $MAINPID
Restart=always

[Install]
WantedBy=multi-user.target graphical.target