Add topologySpreadConstraints configuration to pod spec. (#2530)

* Add topologySpreadConstraints configuration to pod spec.
* Run update-codegen.sh to add deepcopy for new field to the api.
* Reuse configured TopologySpreadConstraints for logical backup.
* Remove x-kubernetes-preserve-unknown-fields and XPreserveUnknownFields.
* Add topologySpreadConstraint example in the complete manifest.
* Add support for helm chart.
* Add documentation for topologySpreadConstraint.
* Update e2e test to patch topologySpreadConstraints into the postgresqls manifest.
* For e2e test, updated the PVC retention policy to remove redundant PVCs.
* Fix e2e test, expected PVC count in end-to-end test after config changes.

manifests/complete-postgres-manifest.yaml

@@ -232,6 +232,12 @@ spec:
 #              values:
 #                - enabled
 
+# Add topology spread constraint to distribute PostgreSQL pods across all nodes labeled with "topology.kubernetes.io/zone".
+#   topologySpreadConstraint:
+#     - maxSkew: 1
+#       topologyKey: topology.kubernetes.io/zone
+#       whenUnsatisfiable: DoNotSchedule
+
 # Enables change data capture streams for defined database tables
 #  streams:
 #  - applicationId: test-app

manifests/postgresql.crd.yaml

@@ -4056,6 +4056,22 @@ spec:
                       type: string
                   type: object
                 type: array
+              topologySpreadConstraints:
+                type: array
+                nullable: true
+                items:
+                  type: object
+                  properties:
+                    maxSkew:
+                      type: integer
+                      format: int32
+                    topologyKey:
+                      type: string
+                    whenUnsatisfiable:
+                      type: string
+                      enum:
+                        - DoNotSchedule
+                        - ScheduleAnyway
               useLoadBalancer:
                 description: |-
                   deprecated load balancer settings maintained for backward compatibility