feat(helm): add option to customize `clusterIP`

Fixes https://github.com/emqx/emqx/issues/10223

Adds an option to set `clusterIP` to a fixed IP if the user wants
that.

changes/ce/feat-10224.en.md

@@ -0,0 +1,2 @@
+Add the option to customize `clusterIP` in Helm chart, so that an user
+may set it to a fixed IP.

deploy/charts/emqx-enterprise/templates/service.yaml

@@ -114,7 +114,7 @@ metadata:
 spec:
   type: ClusterIP
   sessionAffinity: None
-  clusterIP: None
+  clusterIP: {{ .Values.service.clusterIP | default "None" }}
   publishNotReadyAddresses: true
   ports:
   - name: mqtt

deploy/charts/emqx/templates/service.yaml

@@ -114,7 +114,7 @@ metadata:
 spec:
   type: ClusterIP
   sessionAffinity: None
-  clusterIP: None
+  clusterIP: {{ .Values.service.clusterIP | default "None" }}
   publishNotReadyAddresses: true
   ports:
   - name: mqtt

deploy/charts/emqx/values.yaml

@@ -128,6 +128,9 @@ service:
   ## Service type
   ##
   type: ClusterIP
+  ## The cluster IP if one wants to customize it to a fixed value
+  ##
+  clusterIP: None
   ## Port for MQTT
   ##
   mqtt: 1883