Nginx / PHP FPM graceful stop (SIGQUIT): not so graceful

Question

Running nginx 1.9.* / PHP 7.0.* (but exact same behavior in 5.6.* also)

Attempting to gracefully stop a PHP-FPM / nginx combo for node shutdown during maintenance. To do

Answer 1

After struggling with this same situation for a while, I believe I've found the magical config setting to make child processes finish handling requests before dying.

http://php.net/manual/en/install.fpm.configuration.php#process-control-timeout

process_control_timeout

Time limit for child processes to wait for a reaction on signals from master

Basically, by setting this to something like 10s, the child process will wait that long, while handling existing requests before quitting.

Unfortunately, it seems that the php-fpm master process exits immediately, so, inspired by the code here, I wrote a wrapper script:

#!/bin/bash

PHP_FPM_PID='/php-fpm.pid'

wait_for_pid () {
    try=0

    while test $try -lt 35 ; do
        if [ ! -f "$1" ] ; then
            try=''
            break
        fi

        echo -n .
        try=`expr $try + 1`
        sleep 1
    done
}

function clean_up {

    echo "Killing $(cat $PHP_FPM_PID)"

    kill -QUIT `cat $PHP_FPM_PID`
    wait_for_pid $PHP_FPM_PID

    echo "Done!"

    exit 0
}

trap clean_up EXIT

nohup php-fpm --daemonize --pid $PHP_FPM_PID 2>&1 &

while true; do sleep 1; done
# ^ do nothing forever

which waits 35 seconds or until that pid file has been removed (presumably by one of the child processes? I'm still unclear on how it's removed).

Regardless, this wrapper script works well as the CMD for our php-fpm docker container that we're running with Kubernetes.