Make 9router (AI router & token saver) auto-start as a non-root user (ardhi) when the server boots — using a @reboot cron job instead of a systemd unit.

Proven working on Ubuntu 26.04 (systemd) after a real reboot.

Why not systemd / plain `9router`?

Running 9router without -t crashes on a headless server (it waits for an interactive TTY menu that doesn't exist → crash-loop with EADDRINUSE).
A plain @reboot cron calling 9router -t ... directly fails because:
1. cron runs the job as the cron user, not root — so runuser inside is rejected (runuser: may not be used by non-root users).
2. The log file gets created as root, so the ardhi process can't write to it (cannot create /home/ardhi/9router.log: Permission denied).
3. The process is killed when cron's boot session tears down (Session terminated, killing shell... killed.).

This project solves all three with a tiny wrapper script + an adaptive crontab.

Files

File	Purpose
`start-9router.sh`	Detached launcher. Drops to `ardhi` if run as root, runs directly if already `ardhi`. Uses absolute paths (cron `@reboot` has a minimal `PATH`).
`install.sh`	One-shot setup: installs the wrapper, fixes log ownership, and registers the `@reboot` cron as root.
`README.md`	This file.

Step-by-step (manual)

1. Install the wrapper

sudo cp start-9router.sh /usr/local/bin/start-9router.sh
sudo chmod +x /usr/local/bin/start-9router.sh

2. Fix log-file ownership (so `ardhi` can write)

sudo touch /home/ardhi/9router.log
sudo chown ardhi:ardhi /home/ardhi/9router.log
sudo chmod 644 /home/ardhi/9router.log

3. Register the `@reboot` cron as ROOT

Must be root's crontab, because the wrapper uses runuser to drop privileges.

sudo crontab -l 2>/dev/null; echo "@reboot /usr/local/bin/start-9router.sh" | sudo crontab -

Verify:

sudo crontab -l
# -> @reboot /usr/local/bin/start-9router.sh

4. Make sure the cron daemon is running

sudo systemctl enable cron
sudo systemctl start cron
systemctl is-active cron   # -> active

5. Disable the (broken) systemd unit if it exists

sudo systemctl disable 9router 2>/dev/null || true

6. Reboot and verify

sudo reboot

After the server is back:

# port should be LISTEN
ss -ltnp | grep 20128

# process should run as ardhi
ps -eo pid,user,args | grep -E '9router -t|next-server' | grep -v grep

# live check
curl -s -o /dev/null -w "%{http_code}\n" http://127.0.0.1:20128/v1/models   # -> 200

Dashboard: http://127.0.0.1:20128/dashboard API endpoint for CLI tools: http://127.0.0.1:20128/v1

Or just run the installer

sudo ./install.sh

Then reboot.

How the wrapper works

if [ "$(id -u)" = "0" ]; then
  # root (e.g. root's @reboot cron) -> drop to ardhi
  setsid runuser -u ardhi -- sh -c "exec '9router' -t -n --host 127.0.0.1 --port 20128 >> LOG 2>&1 < /dev/null" &
else
  # already ardhi -> run directly
  setsid 9router -t -n --host 127.0.0.1 --port 20128 >> LOG 2>&1 < /dev/null &
fi

setsid + < /dev/null → detaches the process from cron's session so it survives the boot-session teardown.
Absolute paths (/usr/bin/setsid, /usr/sbin/runuser, /usr/local/bin/9router) → required because cron @reboot runs with a minimal PATH.
The redirect happens inside runuser, so ardhi (not root) owns the log file.

Notes / caveats

@reboot cron starts the service at boot but does not auto-restart it if the parent -t process dies. For extra safety you could add a per-minute watchdog cron that checks the port and re-launches the wrapper if needed.
Change the user (ardhi), port (20128), or bind host (127.0.0.1) by editing the wrapper directly.
This setup was validated on the 9router@0.5.50 standalone build, which crashes when launched without -t on a headless machine.

License

MIT — use freely.

README.md

9router Start on Boot (without systemd)

Why not systemd / plain 9router?