core: pin coredns to rpi workers

infrastructure/core/coredns-deployment.yaml

@@ -81,6 +81,20 @@ spec:
             - name: custom-config-volume
               mountPath: /etc/coredns/custom
               readOnly: true
+      affinity:
+        nodeAffinity:
+          requiredDuringSchedulingIgnoredDuringExecution:
+            nodeSelectorTerms:
+              - matchExpressions:
+                  - key: hardware
+                    operator: In
+                    values:
+                      - rpi5
+                      - rpi4
+                  - key: node-role.kubernetes.io/worker
+                    operator: In
+                    values:
+                      - "true"
       dnsPolicy: Default
       nodeSelector:
         kubernetes.io/os: linux