Nginx – Why does Apache receive SIGTERM and just stop

apache-2.4debiannginxweb-server

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

Best Answer

Use auditd to log all of the kill syscalls. -S kill in an audit.rules file. See How to use audit to monitor a specific SYSCALL?. The log entries will contain the pid, uid, and exe of every kill, find the one right before httpd shuts down.

I will guess this is a log rotate script that isn't restarting correctly.