I have this upstart script

When I run: sudo start poxa it starts the process but when I run: initctl list it shows me that is is stop/waiting but when I check ps aux | grep poxa it show the process.

And, as expected, when I try to stop it: sudo stop poxa it returns: stop: unknown instance:

# Upstart Configuration
# put on /etc/init
description     "Poxa"
author          "Poxa"

start on (filesystem or runlevel [2345])
stop on runlevel [!2345]

#respawn limit 10 5
umask 022

console none

pre-start script
    test -x /home/ec2-user/poxa/rel/poxa/bin/poxa || { stop; exit 0; }
end script

pre-stop script
        echo "[`date -u +%Y-%m-%dT%T.%3NZ`] Stoping..." >> /var/log/poxa.log 2>&1
end script

        export HOME=/home/ec2-user
        echo "[`date -u +%Y-%m-%dT%T.%3NZ`] Starting..." >> /var/log/poxa.log 2>&1
        exec /home/ec2-user/poxa/rel/poxa/bin/poxa start >> /var/log/poxa.log 2>&1
end script

ps aux | grep poxa

root     29032  0.0  0.1  13656  1720 ?        S    11:42   0:00 /usr/local/lib/erlang/erts-7.0/bin/run_erl -daemon /home/ec2-user/poxa/rel/poxa/tmp/erl_pipes/poxa/ /home/ec2-user/poxa/rel/poxa/log exec "/home/ec2-user/poxa/rel/poxa/bin/poxa" "console"
root     29033  0.3  2.0 318992 21100 pts/1    Ssl+ 11:42   0:00 /usr/local/lib/erlang/erts-7.0/bin/beam -- -root /home/ec2-user/poxa/rel/poxa -progname home/ec2-user/poxa/rel/poxa/releases/0.4.3/poxa.sh -- -home /home/ec2-user -- -boot /home/ec2-user/poxa/rel/poxa/releases/0.4.3/poxa -boot_var ERTS_LIB_DIR /usr/local/lib/erlang/erts-7.0/../lib -config /home/ec2-user/poxa/rel/poxa/running-config/sys.config -pa /home/ec2-user/poxa/rel/poxa/lib/consolidated -name poxa@ -setcookie
poxa -user Elixir.IEx.CLI -extra --no-halt +iex -- console

I have made this: http://upstart.ubuntu.com/cookbook/#how-to-establish-fork-count to get the fork count but it returns 44!

  • 1
    what does syslog have regarding this process ?
    – PKumar
    Nov 27 '15 at 11:28
  • 1
    @PKumar I don't have it installed but with ps aux | grep poxa I can see the process running
    – user23907
    Nov 27 '15 at 11:32
  • 1
    then upstart is unable to track running pid check log file while starting and stoping the service
    – PKumar
    Nov 27 '15 at 11:34
  • 1
    @PKumar yes, that's exactly the problem and I have no idea why upstart is not tracking it. The log is generated correctly when I run sudo start poxa but since it doesn't track the PID I can't stop it, upstart is considering it as a stopped job. Maybe forcing a PID?
    – user23907
    Nov 27 '15 at 11:39
  • 1
    @PKumar I have added the output when checking for the poxa process, as you can see it has two processes running
    – user23907
    Nov 27 '15 at 11:45

Upstart daemon works with three daemon mode: no expect, expect fork, expect daemon, 6.13.5 Implications of Misspecifying expect

As you can see at there, you need to check the process fork count.

If you insert expect fork, the "exec /home/ec2-user/poxa/rel/poxa/bin/poxa start" process needs to fork once and exit. Also it needs to fork twice and exit for expect daemon. The upstart will trace that last child pid.

To run the daemon correctly with the upstart script, you need to check the fork of poxa process.

Following is my example for upstart and simple daemon.

upstart script in /etc/init

# egservice - eg daemon
# This is an example
# upstart script.

description    "egservice"

start on runlevel [2345]
stop on runlevel [!2345]
#LOOK Following line, So egdaemon needs to fork just once.
expect fork

exec /sbin/egdaemon

egdaemon.c for /sbin/egdaemon

#include <stdio.h>

int main()
    /* LOOK following line, just once fork and main does not wait child and die, 
    so new child will be changed to a init's child and also a daemon. */
    int pid = fork();
    if (pid == 0) {
        while (1) {
            printf("Example daemon\n");
    return 0;

And this C source file can be compiled to a executable binary with following command.

$ gcc -o egdaemon egdaemon.c

You can check if adding expect fork( below umask 022 line ) helps. If the poxa binary goes to background this should help upstart to track the pid.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy