[stable/prometheus] Add RollingUpdate for Prometheus node-exporter ds (#1861)

* [stable/prometheus] Add RollingUpdate for Prometheus node-exporter daemonset

By default updateStrategy is `OnDelete` which needs manual deletion of all daemonsets for change to take affect

* Add review suggestions

* Keep default updateStrategy

stable/prometheus/Chart.yaml

@@ -1,5 +1,5 @@
 name: prometheus
-version: 4.6.10
+version: 4.6.11
 description: Prometheus is a monitoring system and time series database.
 home: https://prometheus.io/
 icon: https://raw.githubusercontent.com/prometheus/prometheus.github.io/master/assets/prometheus_logo-cb55bb5c346.png

stable/prometheus/templates/node-exporter-daemonset.yaml

@@ -10,6 +10,10 @@ metadata:
     release: {{ .Release.Name }}
   name: {{ template "prometheus.nodeExporter.fullname" . }}
 spec:
+  {{- if .Values.nodeExporter.updateStrategy }}
+  updateStrategy:
+{{ toYaml .Values.nodeExporter.updateStrategy | indent 4 }}
+  {{- end }}
   template:
     metadata:
     {{- if .Values.nodeExporter.podAnnotations }}

stable/prometheus/values.yaml

@@ -248,6 +248,11 @@ nodeExporter:
     tag: v0.15.0
     pullPolicy: IfNotPresent
 
+  ## Custom Update Strategy
+  ##
+  updateStrategy:
+    type: OnDelete
+
   ## Additional node-exporter container arguments
   ##
   extraArgs: {}