---
title: Run Bun as a daemon with systemd
sidebarTitle: "systemd with Bun"
mode: center
---

[systemd](https://systemd.io) is an init system and service manager for Linux. It manages the startup and control of system processes and services.

---

To run a Bun application as a daemon with **systemd**, create a _service file_ in `/etc/systemd/system/`.

```sh terminal icon="terminal"
cd /etc/systemd/system
touch my-app.service
```

---

Here is a typical service file that runs an application on system start. Use it as a template for your own service. Replace `YOUR_USER` with the name of the user to run the application as. To run as `root`, replace `YOUR_USER` with `root` and `/home/YOUR_USER` with `/root` (root's home directory). For security reasons, we don't recommend running as `root`.

Refer to the [systemd documentation](https://www.freedesktop.org/software/systemd/man/systemd.service.html) for details on each setting.

```ini my-app.service icon="file-code"
[Unit]
# describe the app
Description=My App
# start the app after the network management stack has started
# (this does not wait for the network to be up, see https://systemd.io/NETWORK_ONLINE)
After=network.target

[Service]
# usually you'll use 'simple'
# one of https://www.freedesktop.org/software/systemd/man/systemd.service.html#Type=
Type=simple
# which user to use when starting the app
User=YOUR_USER
# path to your application's root directory
WorkingDirectory=/home/YOUR_USER/path/to/my-app
# the command to start the app
# requires absolute paths
ExecStart=/home/YOUR_USER/.bun/bin/bun run index.ts
# restart policy
# one of {no|on-success|on-failure|on-abnormal|on-watchdog|on-abort|always}
Restart=always

[Install]
# start the app automatically
WantedBy=multi-user.target
```

---

If your application starts a webserver, non-`root` users cannot listen on ports 80 or 443 by default. To allow Bun to listen on these ports when run by a non-`root` user, use the following command. The command requires `sudo` permissions. This step isn't necessary when running as `root`.

```bash terminal icon="terminal"
setcap CAP_NET_BIND_SERVICE=+eip /home/YOUR_USER/.bun/bin/bun
```

The command attaches the capability to the `bun` binary itself. Replacing the binary, for example with `bun upgrade`, removes the capability. Re-run the command after upgrading. Alternatively, add `AmbientCapabilities=CAP_NET_BIND_SERVICE` to the `[Service]` section of the service file instead.

---

With the service file configured, _enable_ the service. Once enabled, it starts automatically on reboot. Enabling the service requires `sudo` permissions.

```bash terminal icon="terminal"
systemctl enable my-app
```

---

To start the service without rebooting, _start_ it manually.

```bash terminal icon="terminal"
systemctl start my-app
```

---

Check the status of your application with `systemctl status`. If the app started successfully, the output looks like this:

```bash terminal icon="terminal"
systemctl status my-app
```

```txt
● my-app.service - My App
     Loaded: loaded (/etc/systemd/system/my-app.service; enabled; preset: enabled)
     Active: active (running) since Thu 2023-10-12 11:34:08 UTC; 1h 8min ago
   Main PID: 309641 (bun)
      Tasks: 3 (limit: 503)
     Memory: 40.9M
        CPU: 1.093s
     CGroup: /system.slice/my-app.service
             └─309641 /home/YOUR_USER/.bun/bin/bun run index.ts
```

---

To update the service, edit the service file, then reload the daemon.

```bash terminal icon="terminal"
systemctl daemon-reload
```

---

For a complete guide to service unit configuration, see the [systemd.service documentation](https://www.freedesktop.org/software/systemd/man/systemd.service.html). Or use this cheatsheet of common commands:

```bash terminal icon="terminal"
systemctl daemon-reload # tell systemd that some files got changed
systemctl enable my-app # enable the app (to allow auto-start)
systemctl disable my-app # disable the app (turns off auto-start)
systemctl start my-app # start the app if is stopped
systemctl stop my-app # stop the app
systemctl restart my-app # restart the app
```