Docker – Managing daemons with supervisor: no foreground mode available

daemondockersupervisord

I'm trying to manage a process with supervisord, but the process does not have an option to run in foreground: it always daemonizes. (That's Zabbix Server).

Is there any way to manage daemons with supervisor? Any tools which will make it run in foreground? Or maybe, use the pidfile somehow?

Best Answer

In order to deal with the problem, we'll need some program running in foreground, which exits whenever the daemon exits, and which also proxies signals to the daemon.

Consider using the following script bash script:

#! /usr/bin/env bash
set -eu

pidfile="/var/run/your-daemon.pid"
command=/usr/sbin/your-daemon

# Proxy signals
function kill_app(){
    kill $(cat $pidfile)
    exit 0 # exit okay
}
trap "kill_app" SIGINT SIGTERM

# Launch daemon
$command
sleep 2

# Loop while the pidfile and the process exist
while [ -f $pidfile ] && kill -0 $(cat $pidfile) ; do
    sleep 0.5
done
exit 1000 # exit unexpected
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