Longhorn: Upgrade from 1.8.1 to 1.9.0

Change-Id: I809890d3f73e85119c5f3d97e53856bd371c8c81
diff --git a/charts/longhorn-1.8.1/templates/servicemonitor.yaml b/charts/longhorn-1.8.1/templates/servicemonitor.yaml
new file mode 100644
index 0000000..3f32961
--- /dev/null
+++ b/charts/longhorn-1.8.1/templates/servicemonitor.yaml
@@ -0,0 +1,40 @@
+{{- if  .Values.metrics.serviceMonitor.enabled -}}
+apiVersion: monitoring.coreos.com/v1
+kind: ServiceMonitor
+metadata:
+  name: longhorn-prometheus-servicemonitor
+  namespace: {{ include "release_namespace" . }}
+  labels:
+    {{- include "longhorn.labels" . | nindent 4 }}
+    name: longhorn-prometheus-servicemonitor
+    {{- with .Values.metrics.serviceMonitor.additionalLabels }}
+      {{- toYaml . | nindent 4 }}
+    {{- end }}
+  {{- with .Values.metrics.serviceMonitor.annotations }}
+  annotations:
+    {{- toYaml . | nindent 4 }}
+  {{- end }}
+spec:
+  selector:
+    matchLabels:
+      app: longhorn-manager
+  namespaceSelector:
+    matchNames:
+    - {{ include "release_namespace" . }}
+  endpoints:
+  - port: manager
+    {{- with .Values.metrics.serviceMonitor.interval }}
+    interval: {{ . }}
+    {{- end }}
+    {{- with .Values.metrics.serviceMonitor.scrapeTimeout }}
+    scrapeTimeout: {{ . }}
+    {{- end }}
+    {{- with .Values.metrics.serviceMonitor.relabelings }}
+    relabelings:
+      {{- toYaml . | nindent 8 }}
+    {{- end }}
+    {{- with .Values.metrics.serviceMonitor.metricRelabelings }}
+    metricRelabelings:
+      {{- toYaml . | nindent 8 }}
+    {{- end }}
+{{- end }}
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