Comment 7 for bug 1581864

Alex Badics (alex.badics.bb) wrote :

Hi,

We are also affected, and I've looked into the source. In main(), the ngx_create_pidfile() gets called right after the ngx_daemon() function. ngx_daemon of course forks, and the parent process exits immediately with exit(0). This is a pure race condition between nginx and systemd.

This is not a problem (other than the scary log), because the PIDFile option is not needed for determining the main PID of nginx (systemd can correctly "guess" the main pid), it's only for removing the file when the service exits.

As far as I can tell, this daemonization is not needed for the systemd service use-case. The service should be Type=simple, and 'daemon off'. The standard file handles get redirected by systemd anyway, and non-stop upgrade cannot be used in this case either. (See: http://nginx.org/en/docs/faq/daemon_master_process_off.html )

If this is too much of a change, another workaround is removing the PIDFile option, and adding the line:
ExecStopPost=/bin/rm -f /run/nginx.pid

Regards,
Alex