linuxunixerlangdaemonsystemd

Why does my Erlang boot script work from console but does not work when run from init system (sysvinit, upstart, systemd)?

I have an Erlang boot script that I can launch like this:

/usr/bin/erl -boot /path/to/my-boot-script

It works when run from console, but fails without any error messages when I run it from systemd. The systemd unit file looks like this:

[Unit]
Description=My daemon written in Erlang

[Service]
Type=simple
ExecStart=/usr/bin/erl -boot /path/to/my-boot-script
Restart=always

[Install]
WantedBy=multi-user.target

The log shows that the system boots properly and then terminates abruptly without any kind of error message. What the hell is going on?

Solution

  • Turns out that you have to pass -noinput parameter to erl. Otherwise it will try to open stdin for reading, fail because there's nothing there and terminate without any kind of error message.

    This works:

    [Unit]
Description=My daemon written in Erlang

[Service]
Type=simple
ExecStart=/usr/bin/erl -noinput -boot /path/to/my-boot-script
Restart=always

[Install]
WantedBy=multi-user.target