support for deployment strategy (#196)

Co-authored-by: larmitage_wh <luke.armitage@williamhill.com>

charts/helm-dashboard/README.md

@@ -71,7 +71,8 @@ The following table lists the configurable parameters of the chart and their def
 | `dashboard.persistence.accessModes`  | Persistent Volume access modes                                                                 | `["ReadWriteOnce"]`                  |
 | `dashboard.persistence.storageClass` | Persistent Volume storage class                                                                | `""`                                 |
 | `dashboard.persistence.size`         | Persistent Volume size                                                                         | `100M`                               |
-| `dashboard.persistence.hostPath`     | Set path in case you want to use local host path volumes (not recommended in production)       | `""`                                 |
+| `dashboard.persistence.hostPath`     | Set path in case you want to use local host path volumes (not recommended in production)       | `""`
+| `updateStrategy.type`                | Set up update strategy for helm-dashboard installation.                                        | `RollingUpdate`                    |             
 
 Specify each parameter using the `--set key=value[,key=value]` argument to `helm install`.
 

charts/helm-dashboard/templates/deployment.yaml

@@ -11,6 +11,7 @@ spec:
   selector:
     matchLabels:
       {{- include "helm-dashboard.selectorLabels" . | nindent 6 }}
+  strategy: {{- toYaml .Values.updateStrategy | nindent 4 }}
   template:
     metadata:
       {{- with .Values.podAnnotations }}
@@ -83,3 +84,4 @@ spec:
         {{- else }}
           emptyDir: { }
         {{- end }}
+

charts/helm-dashboard/values.yaml

@@ -68,6 +68,20 @@ dashboard:
     ##
     size: 100M
   
+## @param.updateStrategy.type Set up update strategy for helm-dashboard installation.
+## Set to Recreate if you use persistent volume that cannot be mounted by more than one pods to make sure the pods is destroyed first.
+## ref: https://kubernetes.io/docs/concepts/workloads/controllers/deployment/#strategy
+## Example:
+## updateStrategy:
+##  type: RollingUpdate
+##  rollingUpdate:
+##    maxSurge: 25%
+##    maxUnavailable: 25%
+##
+updateStrategy:
+  type: RollingUpdate
+
+
 podAnnotations: {}
 
 podSecurityContext: {}
@@ -100,3 +114,4 @@ nodeSelector: {}
 tolerations: []
 
 affinity: {}
+