I've been noticing a lot of Dovecot shut downs lately. I've brought it to the attention of my hosting provider, but they're not being of much help.
Nov 2 10:07:22 srvr dovecot: master: Warning: Killed with signal 15 (by pid=28444 uid=0 code=kill)
Then all of the current IMAP accounts logged in will shut down.
Nov 2 10:07:23 srvr dovecot: master: Dovecot v2.2.32 (dfbe293d4) starting up for lmtp, imap, pop3 (core dumps disabled)
I checked the downtime stats on the server and below is the current trend.
- month of August: down 1 time (total 9sec) - month of September: down 5 times (total 50sec) - month of October: down 22 times (total 8m 59s) - month of November, only 7 days in: down 27 times (total 4m 41s)
You can obviously see that Dovecot's downtime has been increasing. I've searched around exhaustively, but can't seem to find any leads.
I'm on CentOS 6.9 and cPanel 66.0.26. Running CSF + LFD. 1H Guardian and Hive is also running.
I disabled CSF and it still happens.
*** UPDATE 11/12/2017 06:06PM EST
I've disabled 1H Guardian monitoring temporarily on Exim, and Dovecot. Based on the monitoring so far, it seems to have resolved the issue. I will monitor a bit more and see if it's truly the case.
*** UPDATE 11/16/2017 07:50PM EST
After several days of monitoring, it definitely was 1H Guardian causing the constant killing of Exim and Dovecot. Though I don't know exactly why this was happening, I disabled the 2 services in the monitoring.