Add support to customise storagesvc deployment strategy (#3196)

* chart>fission-all/values.yaml: Fix typo in imageppullsecrets

Fix a typo in comments.

* Add support to customise storagesvc deployment strategy

Add suport to `values.yaml` to allow customisation of the storagesvc deployment
strategy. The default is a rolling update with `maxSurge` and `maxUnavailable`
of 25%. Users with ReadWriteOnce persistent storage can use the `Recreate`
strategy.

Issue 3195

charts/fission-all/templates/storagesvc/deployment.yaml

@@ -12,6 +12,12 @@ spec:
     matchLabels:
       svc: storagesvc
       application: fission-storage
+  strategy:
+    type: {{ .Values.storagesvc.deploymentStrategy.type }}
+    {{- if eq .Values.storagesvc.deploymentStrategy.type "RollingUpdate" }}
+    rollingUpdate:
+      {{- toYaml .Values.storagesvc.deploymentStrategy.rollingUpdate | nindent 6}}
+    {{- end }}
   template:
     metadata:
       labels:

charts/fission-all/values.yaml

@@ -31,7 +31,7 @@ imageTag: v1.21.0
 ##
 pullPolicy: IfNotPresent
 
-## imageppullsecrets 
+## imagepullsecrets
 imagePullSecrets: []
 
 ## priorityClassName represents the priority class name to use for Fission components.
@@ -439,6 +439,16 @@ storagesvc:
   ##
   resources: {}
 
+  ## Deployment strategy defaults to RollingUpdate but use Recreate if new pods fail to
+  ## attach to the volume until the old pod has released it.
+  ## deploymentStrategy:
+  ##   type: Recreate
+  deploymentStrategy:
+    type: RollingUpdate
+    rollingUpdate:
+      maxSurge: 25%
+      maxUnavailable: 25%
+
   ## Archive pruner removes archives from storage which are not referenced by any package.
   archivePruner:
     enabled: true