> I did some further debugging and it is the > /usr/lib/apt/apt.systemd.daily script executed by apt-daily systemd > service unit which updates the package index from the sources:
I configured cron with one minute interval to log the output of "apt policy" with a timestamp into a log file in order to understand when exactly the repository list is messed up. Turns out, that /usr/lib/apt/apt.systemd.daily script executed by apt-daily systemd service unit does not mess up the repository list. It happened between "Sat Jun 8 06:25:01 UTC 2019" and "Sat Jun 8 06:26:01 UTC 2019". When I check the logs for 06:00 to 06:30 time-period, then following was logged: $ sudo journalctl --since "2019-06-08 06:00:00" --until "2019-06-08 06:30:00" -- Logs begin at Mon 2019-05-13 19:38:07 UTC, end at Sat 2019-06-08 08:11:24 UTC. -- Jun 08 06:25:04 vps systemd[1]: Reloading The Apache HTTP Server. Jun 08 06:25:05 vps systemd[1]: Reloaded The Apache HTTP Server. Jun 08 06:25:05 vps liblogging-stdlog[556]: [origin software="rsyslogd" swVersion="8.24.0" x-pid="556" x-info="http://www.rsyslog.com"] rsyslogd was HUPed $ What and why is sending those signals to processes? Could it somehow affect the repository list..? thanks, Martin