For the record, you should use an init system (most probably you will have systemd). This is the correct way. Go learn this and you will have a much easier life later on.
You can use
screen to keep your app running. Start an SSH session, run a
screen session inside it, run your app inside it and detach from the
Also, as the dirtiest way:
_build/prod/rel/app/bin/app start >/dev/null 2>&1 &
& at the end start the command in background, and redirection to
/dev/null is for safety measures. Some apps will just crash if their “output” screen is closed. You can replace
/dev/null with a file name so you can see your logs.
disown makes your background app detached from your current shell, so when you close your SSH session, your background app won’t be killed.