new file mode 100644
index 0000000..9d19baa
@@ -0,0 +1,16 @@
+---
+visibility: public
+---
+
+# systemd
+
+Linux init system and service manager. manages long-running processes on the server.
+
+**role in the deploy chain:** the supervisor for everything on [[AWS Lightsail]] — ensures [[gunicorn]], [[nginx]], and other services start on boot and restart if they crash. each service gets a unit file defining how to run it.
+
+**key commands:**
+- `systemctl start/stop/restart service` — manage services
+- `systemctl enable service` — start on boot
+- `journalctl -u service` — view logs
+
+**local equivalent:** on the mac, tmux + [[tmux-continuum]] serves a similar role — keeping sessions alive across reboots. but systemd is the real deal for production.
\ No newline at end of file