Helm charts: Add option for using a StatefulSet with persistent storage

charts/viking-service/templates/_helpers.tpl

@@ -45,14 +45,4 @@ We truncate at 63 chars because some Kubernetes name fields are limited to this
 {{- end -}}
 {{- end -}}
 
-{{/*
-Return the appropriate apiVersion for deployment.
-*/}}
-{{- define "deployment.apiVersion" -}}
-{{- if semverCompare ">=1.9-0" .Capabilities.KubeVersion.GitVersion -}}
-{{- print "apps/v1" -}}
-{{- else -}}
-{{- print "extensions/v1beta1" -}}
-{{- end -}}
-{{- end -}}
 

charts/viking-service/templates/deployment.yaml

-apiVersion: {{ template "deployment.apiVersion" . }}
-kind: Deployment
+apiVersion: apps/v1
+kind: {{ .Values.vikingService.kind }}
 metadata:
   labels:
     app.kubernetes.io/name: {{ template "viking-service.name" . }}
@@ -14,17 +14,33 @@ metadata:
     {{ toYaml .Values.vikingService.annotations | nindent 4}}
 {{- end }}
 spec:
+{{/* Try to collect kind specific differences here */}}
+{{- if eq .Values.vikingService.kind "Deployment" }}
+  minReadySeconds: {{ .Values.vikingService.minReadySeconds }}
+{{- else }}
+  serviceName: {{ template "viking-service.fullname" . }}
+  {{- if .Values.vikingService.persistentVolume.enabled }}
+  volumeClaimTemplates:
+    - metadata:
+        name: persistent-storage
+      spec:
+        accessModes: [ "ReadWriteOnce" ]
+        storageClassName: {{ .Values.vikingService.persistentVolume.storageClass | quote }}
+        resources:
+          requests:
+            storage: {{ .Values.vikingService.persistentVolume.size }}
+  {{- end }}
+{{- end }}
   selector:
     matchLabels:
       app.kubernetes.io/name: {{ template "viking-service.name" . }}
       app.kubernetes.io/instance: {{ .Release.Name }}
+  {{- if .Values.vikingService.updateStrategy }}
+  strategy:
+    {{- toYaml .Values.vikingService.updateStrategy | nindent 4 }}
+  {{- end }}
   replicas: {{ .Values.vikingService.replicaCount }}
   revisionHistoryLimit: {{ .Values.revisionHistoryLimit }}
-{{- if .Values.vikingService.updateStrategy }}
-  strategy:
-    {{ toYaml .Values.vikingService.updateStrategy | nindent 4 }}
-{{- end }}
-  minReadySeconds: {{ .Values.vikingService.minReadySeconds }}
   template:
     metadata:
     {{- if .Values.vikingService.podAnnotations }}
@@ -105,6 +121,10 @@ spec:
               mountPath: "/run/varnish-home"
             - name: run-offload
               mountPath: "/run/offload"
+            {{- if (and (eq .Values.vikingService.kind "StatefulSet") .Values.vikingService.persistentVolume.enabled) }}
+            - name: persistent-storage
+              mountPath: "/run/varnish-home/persistent-storage"
+            {{- end }}
           securityContext:
             readOnlyRootFilesystem: true
           resources:

charts/viking-service/values.yaml

@@ -21,6 +21,19 @@ vikingService:
 
     resources: {}
 
+  # Choose from Deployment or StatefulSet
+  kind: Deployment
+
+  # Only applicable if kind is StatefulSet
+  persistentVolume:
+    enabled: false
+    storageClass: null
+    size: 1Gi
+
+  # Only applicable if kind is Deployment
+  # minReadySeconds to avoid killing pods before we are ready
+  minReadySeconds: 0
+
   secrets:
     admin: "21d0ac6c-83d5-11ea-8acc-1ff3820da75e"
     dataplaneapi: "e24bb312-cb21-46d6-aaec-8ae676f06fea"
@@ -62,10 +75,6 @@ vikingService:
   #    maxUnavailable: 1
   #  type: RollingUpdate
 
-  # minReadySeconds to avoid killing pods before we are ready
-  ##
-  minReadySeconds: 0
-
   ## Node tolerations for server scheduling to nodes with taints
   ## Ref: https://kubernetes.io/docs/concepts/configuration/assign-pod-node/
   ##