diff --git a/k8s/operators/kube-prometheus/prometheus-patch.yaml b/k8s/operators/kube-prometheus/prometheus-patch.yaml
index 277aa66..cbffac2 100644
--- a/k8s/operators/kube-prometheus/prometheus-patch.yaml
+++ b/k8s/operators/kube-prometheus/prometheus-patch.yaml
@@ -28,3 +28,7 @@
     objectStorageConfig:
       key: thanos.yaml
       name: thanos-objstore
+- op: add
+  path: /spec/externalLabels
+  value:
+    cluster: k3s