最近Debian 9にアップグレードしたサーバーの中には、毎日奇妙なsyslogメッセージが生成されます（logcheckで報告されています）。
Oct 27 06:25:08 foo systemd[1]: [email protected]: Killing process 12270 (kill) with signal SIGKILL.
時間はcron.dailyのようで、サービス名もno one/no groupのUIDのように見えますが、なぜ死んで初めに何をするのでしょうか？
その当時、より多くのsyslogラインがありました。このブロックは数回繰り返されます。
Oct 27 06:25:08 svn systemd[1]: Created slice User Slice of nobody.
Oct 27 06:25:08 svn systemd[1]: Starting User Manager for UID 65534...
Oct 27 06:25:08 svn systemd[1]: Started Session 1377 of user nobody.
Oct 27 06:25:08 svn systemd[12264]: Reached target Paths.
Oct 27 06:25:08 svn systemd[12264]: Listening on GnuPG cryptographic agent (access for web browsers).
Oct 27 06:25:08 svn systemd[12264]: Listening on GnuPG network certificate management daemon.
Oct 27 06:25:08 svn systemd[12264]: Reached target Timers.
Oct 27 06:25:08 svn systemd[12264]: Listening on GnuPG cryptographic agent and passphrase cache (restricted).
Oct 27 06:25:08 svn systemd[12264]: Listening on GnuPG cryptographic agent (ssh-agent emulation).
Oct 27 06:25:08 svn systemd[12264]: Listening on GnuPG cryptographic agent and passphrase cache.
Oct 27 06:25:08 svn systemd[12264]: Reached target Sockets.
Oct 27 06:25:08 svn systemd[12264]: Reached target Basic System.
Oct 27 06:25:08 svn systemd[12264]: Reached target Default.
Oct 27 06:25:08 svn systemd[12264]: Startup finished in 12ms.
Oct 27 06:25:08 svn systemd[1]: Started User Manager for UID 65534.
Oct 27 06:25:08 svn systemd[1]: Stopping User Manager for UID 65534...
Oct 27 06:25:08 svn systemd[12264]: Stopped target Default.
Oct 27 06:25:08 svn systemd[12264]: Stopped target Basic System.
Oct 27 06:25:08 svn systemd[12264]: Stopped target Sockets.
Oct 27 06:25:08 svn systemd[12264]: Closed GnuPG cryptographic agent and passphrase cache.
Oct 27 06:25:08 svn systemd[12264]: Closed GnuPG network certificate management daemon.
Oct 27 06:25:08 svn systemd[12264]: Closed GnuPG cryptographic agent (access for web browsers).
Oct 27 06:25:08 svn systemd[12264]: Closed GnuPG cryptographic agent and passphrase cache (restricted).
Oct 27 06:25:08 svn systemd[12264]: Closed GnuPG cryptographic agent (ssh-agent emulation).
Oct 27 06:25:08 svn systemd[12264]: Reached target Shutdown.
Oct 27 06:25:08 svn systemd[12264]: Starting Exit the Session...
Oct 27 06:25:08 svn systemd[12264]: Stopped target Timers.
Oct 27 06:25:08 svn systemd[12264]: Stopped target Paths.
Oct 27 06:25:08 svn systemd[12264]: Received SIGRTMIN+24 from PID 12270 (kill).
Oct 27 06:25:08 svn systemd[1]: [email protected]: Killing process 12270 (kill) with signal SIGKILL.
Oct 27 06:25:08 svn systemd[1]: Stopped User Manager for UID 65534.
Oct 27 06:25:08 svn systemd[1]: Removed slice User Slice of nobody.
Oct 27 06:25:08 svn systemd[1]: Created slice User Slice of nobody.
PID 12264 syslog/syslog.1 にエントリがなくなりました。