We run New Relic extensively (at least a few hundred instances) for
our customers. Here's the native systemd service unit we use. I'm sure
we'd tweak it if we revisited it now, but it certainly works.
[Unit]
Description=New Relic Global Daemon
[Service]
ExecStart=/usr/bin/newrelic-daemon -c
/etc/newrelic/newrelic_global.cfg -l /var/log/newrelic-daemon.log -p
/var/run/newrelic-daemon.pid
ExecStop=/usr/bin/newrelic-daemon -c /etc/newrelic/newrelic_global.cfg
-C stop /dev/null 2>&1
PIDFile=/var/run/newrelic-daemon.pid
TimeoutSec=15
[Install]
WantedBy=multi-user.target