Insights doesn't gather local modifications of systemd unit files

[msekletar]

I've noticed that insights parsers for systemd unit files obtain data mostly using simple_file() spec. This is probably not the best solution. systemd unit files can reside in multiple locations in the filesystem.

Most commonly unit files get copied to /etc/systemd/system/ directory for local modifications and such unit file then takes precedence over the unit file with the same name in /usr/lib/systemd/system. IOW, by gathering unit file from /usr we are pulling in old version which is most likely not running anymore.

Also, unit files can be extended using drop-in configuration snippets. These extensions are again not captured by parsing single file.

I think that all parsers which now use simple_file("/usr/lib/systemd/system/<unit>) should be patched to use simple_command("/usr/bin/systemctl cat <unit>") instead.