Remove NewRelic agent

* For the main service:

/etc/init.d/newrelic-sysmond stop

apt-get --purge remove newrelic-sysmond

* For the PHP agent:

newrelic-install purge

apt-get --purge remove newrelic-php5-common

dpkg -l | grep newrelic

(nothing should show when you run the above, if anything, proceed to manually removing the remaining services)

service nginx restart

service php7.0-fpm restart

* For MySQL agent:

cd /root/newrelic-npi

./npi stop com.newrelic.plugins.mysql.instance

./npi remove-service com.newrelic.plugins.mysql.instance

./npi remove com.newrelic.plugins.mysql.instance