I've noticed that some log files, especially /var/log/syslog were empty.
After investigating, I've realized that it was happening after a log
rotation by logrotate.
The old mechanism, `invoke-rc.d rsyslog rotate` isn't working anymore on
Debian 10. It will fail with a not so explicit message :
[FAIL] Closing open files: rsyslogd failed!
Long story short, it seems that the pid file (`/run/rsyslogd.pid`) isn't
created any more, so start-stop-daemon as used by /etc/init.d/rsyslog
will fail. Explaining the error message.
Debian 10 rsyslog now brings `/usr/lib/rsyslog/rsyslog-rotate` that is
used by logrotate. It will send the signal HUP the 'right' way, so
rsyslog will be aware of the log rotation.
Sadly, this script isn't present in Debian 9 nor 8, so the logrotate
configuration for rsyslog is now a template, using the right command for
the right version.
Jérémy Lecour
Ludovic Poujol