I'm testing a new server... had trouble with PHP-FPM not restarting after a reboot.
Here's a log snip from /var/log/php7.0-fpm.log:
[09-Aug-2018 13:34:41] NOTICE: Terminating ...
[09-Aug-2018 13:34:41] NOTICE: exiting, bye-bye!
[09-Aug-2018 13:34:42] NOTICE: fpm is running, pid 10340
[09-Aug-2018 13:34:42] NOTICE: ready to handle connections
[09-Aug-2018 13:34:42] NOTICE: systemd monitor interval set to 10000ms
[10-Aug-2018 01:32:14] NOTICE: Terminating ...
[10-Aug-2018 01:32:14] NOTICE: exiting, bye-bye!
[10-Aug-2018 13:59:47] NOTICE: fpm is running, pid 5453
[10-Aug-2018 13:59:47] NOTICE: ready to handle connections
[10-Aug-2018 13:59:47] NOTICE: systemd monitor interval set to 10000ms
On Aug 9, at 13:34:41 the FPM went down, but the next second (:42) it restarted, so that was normal.
But on Aug 10, at 1:32:14am the FPM went down when I rebooted, but didn't come back up until 13 hours later when I found it was down and forced it to start.
I have told it "systemctl enable php7.0-fpm.service" hoping that will solve the issue, but I'm concerned my system isn't stable.
Anyone have suggestions about how to "keep PHP-FPM running" ???
Are you runnig APC Cache?
There is a post about fpm and apc cache on stack exchange titled "constantly have to reload php fpm" Cant copy its url from app on my phone sorry. Not sure if this applies to your current problem.
https://ajecreative.com.au