Ubuntu 16.04 moved everyone to systemd and PHP 7 at once

The April LTS changes two things at the same time, and either one alone would be a migration. service still works because systemd ships a compatibility shim, which is why the change is easy to not notice until something needs debugging.

# 14.04
service php5-fpm restart
tail -f /var/log/upstart/php5-fpm.log

# 16.04
systemctl restart php7.0-fpm
journalctl -u php7.0-fpm -f

The package names change with the version, so every provisioning script mentioning php5-fpm needs editing, and the socket path moves from /var/run/php5-fpm.sock to /var/run/php/php7.0-fpm.sock — which breaks nginx in a way that reports only “connection refused”. Upgrading in place from 14.04 keeps Upstart until reboot, so a half-migrated box is a real state to be in.