Since the update of the rootserver to Ubuntu Saucy I've been experiencing strange shutdowns of proftpd. Logfiles only showed :
2013-12-29 06:25:27,355 zulu203 proftpd zulu203.server4you.de: ProFTPD killed (signal 15) 2013-12-29 06:25:27,457 zulu203 proftpd zulu203.server4you.de: ProFTPD 1.3.5rc3 standalone mode SHUTDOWN
Server could then be restarted (service proftpd restart) without any warning or error message.
I finally found the root cause : logrotate, when it rotates the logs, restarts the proftpd daemon. To do this, it issues the command
invoke-rc.d proftpd restart
Issuing this command manually on the command line, I see the messages :
* Stopping ftp server proftpd [ OK ] * Starting ftp server proftpd [ OK ]
but still no daemon running !
I then found followind bug report, which suggests that the start of the daemon comes too soon after the shutdown, and therefore silently fails. The proposed solution is to replace
signal stop 1 start
signal stop 1 sleep 2 start
in order to let the daemon shut down properly.