add activation script to clear k3s

modules/k3s/default.nix

@@ -40,5 +40,27 @@ in
         "ubuntu"
       ];
     };
+
+    system.activationScripts.cleanK3sManifests = {
+      text = ''
+        MANIFESTS_DIR="/var/lib/rancher/k3s/server/manifests"
+        NIX_MANIFESTS="${builtins.concatStringsSep " " (builtins.attrNames config.services.k3s.manifests)}"
+        DEFAULT_MANIFESTS="ccm coredns local-storage rolebindings runtimes traefik"
+
+        echo "Cleaning up K3s manifests"
+
+        for file in $MANIFESTS_DIR/*.yaml; do
+          [ -f "$file" ] || echo "not a file"; continue
+          name=$(basename "$file" .yaml)
+          if ! (echo "$NIX_MANIFESTS $DEFAULT_MANIFESTS" | grep -qw $name); then
+            echo "Stale manifest found, deleting $name.yaml"
+            k3s kubectl delete -f "$file" --ignore-not-found=true 2>/dev/null || true
+            rm -f "$file"
+          fi
+        done
+
+        echo "Done"
+      '';
+    };
   };
 }