feat(wireguard): setup K8s to FritzBox Site-to-Site VPN

.gitattributes

@@ -2,3 +2,4 @@
 *.secret.yaml filter=git-crypt diff=git-crypt
 *.secret.values filter=git-crypt diff=git-crypt
 *.secret.sh filter=git-crypt diff=git-crypt
+*.secret.conf filter=git-crypt diff=git-crypt

fritzbox/README.md

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+# FritzBox Wireguard Setup
+
+This folder contains configuration and documentation for connecting your FritzBox router (home network) to the Kubernetes cluster via a Wireguard Site-to-Site VPN.
+
+## 1. Prerequisites
+- Your FritzBox must be running FRITZ!OS 7.50+ (Tested with 8.25).
+- The Kubernetes Wireguard endpoint (`k8s/wireguard`) must be deployed and running on `vpn.haumdaucher.de`.
+
+## 2. Connecting the FritzBox
+
+The FritzBox will be configured to connect to the cluster via a "LAN-to-LAN" coupling. Since we prefer "infrastructure as code", we have pre-generated the exact configuration file. For FritzBox specifically, this requires a manual import step.
+
+1. Locate the file `fritzbox-wireguard.secret.conf` in this directory. 
+2. Ensure you have unlocked `git-crypt` so you can read its decrypted contents.
+3. Open your FritzBox Web Interface (usually `http://fritz.box`).
+4. Navigate to **Internet > Permit Access > VPN (WireGuard)**.
+5. Click on **Add Connection** (or "Verbindung hinzufügen").
+6. Select **Connect networks or establish special connections** (Netzwerke koppeln oder spezielle Verbindungen herstellen).
+7. Ask if it has been set up on the other side -> choose **Yes** (or choose to upload a config file directly).
+8. Choose **Upload a configuration file** and select the decrypted `fritzbox-wireguard.secret.conf` file.
+9. Finish the setup.
+
+The FritzBox will immediately try to connect to `vpn.haumdaucher.de:51820`.
+
+## 3. Verifying the Connection
+
+### From the Kubernetes Side
+Connect to your cluster and check the Wireguard pod logs:
+```bash
+# Get the pod name
+kubectl get pods -n wireguard
+
+# Execute into the pod to check connection status
+kubectl exec -it <pod-name> -n wireguard -- wg show
+```
+You should see a peer connected and the `latest handshake` timestamp indicating a successful connection.
+
+### Bidirectional Ping Test
+1. **Cluster -> Home Network:**
+   Exec into any pod in your cluster (e.g., a toolbox or home-assistant pod) and ping a device on your local network:
+   ```bash
+   ping 192.168.10.1  # Ping your FritzBox local IP
+   ```
+2. **Home Network -> Cluster:**
+   From your laptop at home, try to ping a known K8s Service IP (e.g., `10.233.0.1` for kubernetes default service, or a specific pod IP):
+   ```bash
+   ping 10.233.0.1
+   ```
+
+## Backups
+Any future manual configurations, firmware backups, or notes related to the FritzBox should be stored within this `fritzbox/` folder. Use `.secret` extensions for any files containing sensitive tokens or passwords.

k8s/wireguard/deployment.yaml

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+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: wireguard
+  namespace: wireguard
+  labels:
+    app: wireguard
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: wireguard
+  template:
+    metadata:
+      labels:
+        app: wireguard
+    spec:
+      hostNetwork: true
+      containers:
+      - name: wireguard
+        image: alpine:latest
+        command: ["/bin/sh", "-c"]
+        args:
+          - |
+            apk add --no-cache wireguard-tools iptables
+            cp /config/wg0.conf /etc/wireguard/wg0.conf
+            chmod 600 /etc/wireguard/wg0.conf
+            wg-quick up wg0
+            echo "Wireguard is up"
+            trap "wg-quick down wg0" SIGINT SIGTERM
+            sleep infinity &
+            wait
+        securityContext:
+          privileged: true
+          capabilities:
+            add:
+              - NET_ADMIN
+              - SYS_MODULE
+        volumeMounts:
+        - name: wg-config
+          mountPath: /config/wg0.conf
+          subPath: wg0.conf
+          readOnly: true
+        - name: lib-modules
+          mountPath: /lib/modules
+          readOnly: true
+      volumes:
+      - name: wg-config
+        secret:
+          secretName: wireguard-config
+      - name: lib-modules
+        hostPath:
+          path: /lib/modules

k8s/wireguard/kustomization.yaml

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+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+
+namespace: wireguard
+
+resources:
+  - namespace.yaml
+  - secret.secret.yaml
+  - deployment.yaml

k8s/wireguard/namespace.yaml

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+apiVersion: v1
+kind: Namespace
+metadata:
+  name: wireguard