docs: add automated upgrades docs

CHANGELOG.md

@@ -1,5 +1,9 @@
 # CHANGELOG
 
+## Enable automatic updates on control plane / 2024-11-14
+
+See [os/automated-upgrades](/docs/os/automated-upgrades.md).
+
 ## Update Kubernetes to v1.30.4 / 2024-08-30
 
 - Upgrade the cluster to Kubernetes (k3s) version v1.30 (`v1.30.4`)

docs/os/automated-upgrades.md

@@ -0,0 +1,33 @@
+# os automated upgrades
+
+Rocky Linux is configured to automatically upgrade. The OS reboot is then
+coordinated with Kubernetes nodes via [Kured](https://kured.dev/).
+
+Inspired by [github.com/khuedoan/homelab](https://github.com/khuedoan/homelab/tree/da9afc6de0f27c1d431ae9ecf4f899cb6aedcd15/metal/roles/automatic_upgrade).
+
+- [DNF automatic updates (Fedora docs)](https://docs.fedoraproject.org/en-US/quick-docs/autoupdates/)
+
+## Setup
+
+1. Install
+
+    ```bash
+    dnf update -y
+
+    dnf install -y dnf-automatic dnf-utils
+    ```
+
+2. Configure
+
+    ```conf
+    [commands]
+    upgrade_type = default
+    apply_updates = yes
+    ```
+
+3. Start
+
+    ```bash
+    systemctl enable dnf-automatic.timer
+    systemctl start dnf-automatic.timer
+    ```