CLD-866: toplogySpreadConstraints feature changes commit (#154)

Author: sumanthravipati

README.md

@@ -115,6 +115,7 @@ Following table lists all the parameters supported by the latest MarkLogic Helm
 | `license.key`                                       | Set MarkLogic license key installed                                                                                                                                                    | `""`                       |
 | `license.licensee`                                  | Set MarkLogic licensee information                                                                                                                                                     | `""`                       |
 | `affinity`                                          | Affinity for MarkLogic pods assignment                                                                                                                                                 | `{}`                       |
+| `topologySpreadConstraints`                         | POD Topology Spread Constraints to spread Pods across cluster                                                                                                                                                    | `[]`                       |
 | `nodeSelector`                                      | Node labels for MarkLogic pods assignment                                                                                                                                              | `{}`                       |
 | `persistence.enabled`                               | Parameter to enable MarkLogic data persistence using Persistence Volume Claim (PVC). If set to false, EmptyDir will be used.                                                           | `true`                     |
 | `persistence.storageClass`                          | Storage class for MarkLogic data volume, leave empty to use the default storage class                                                                                                  | `""`                       |

charts/templates/statefulset.yaml

@@ -22,6 +22,9 @@ spec:
       {{- with .Values.affinity }}
       affinity: {{- toYaml . | nindent 8}}
       {{- end }}
+      {{- with .Values.topologySpreadConstraints }}
+      topologySpreadConstraints: {{- toYaml . | nindent 6}}
+      {{- end }}
       terminationGracePeriodSeconds: {{ .Values.terminationGracePeriod }}
       {{- if ne .Values.bootstrapHostName "" }}
       initContainers: 

charts/values.yaml

@@ -93,6 +93,16 @@ affinity:
             - marklogic
         topologyKey: kubernetes.io/hostname
 
+## Configure POD Topology Spread Constraints to spread Pods across cluster
+## ref: https://kubernetes.io/docs/concepts/scheduling-eviction/topology-spread-constraints/
+topologySpreadConstraints: []
+  # - maxSkew: 1
+  #   topologyKey: topology.kubernetes.io/zone
+  #   whenUnsatisfiable: ScheduleAnyway
+  #   labelSelector:
+  #     matchLabels:
+  #       app.kubernetes.io/name: marklogic
+
 ## Configure NodeSelector property for scheduling pods to nodes
 ## ref: https://kubernetes.io/docs/tasks/configure-pod-container/assign-pods-nodes/#create-a-pod-that-gets-scheduled-to-your-chosen-node
 nodeSelector: {}