I have a server running nginx for static content, with apache behind it, running php and python code.
About once a day Apache just quits, leaving Nginx serving a 502 Bad Gateway error. All I can find in the logs is Apache received SIGTERM, no other details.
[mpm_prefork:notice] [pid 11811] AH00169: caught SIGTERM, shutting down
It has been running properly for some time now, with no maintenance other than running out of disk space. I did some SSL proxy configuration a few months ago. Running Debian Jessie