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.

pkg/cluster/k8sres.go

@@ -612,6 +612,13 @@ func generatePodAntiAffinity(podAffinityTerm v1.PodAffinityTerm, preferredDuring
 	return podAntiAffinity
 }
 
+func generateTopologySpreadConstraints(labels labels.Set, topologySpreadConstraints []v1.TopologySpreadConstraint) []v1.TopologySpreadConstraint {
+	for _, topologySpreadConstraint := range topologySpreadConstraints {
+		topologySpreadConstraint.LabelSelector = &metav1.LabelSelector{MatchLabels: labels}
+	}
+	return topologySpreadConstraints
+}
+
 func tolerations(tolerationsSpec *[]v1.Toleration, podToleration map[string]string) []v1.Toleration {
 	// allow to override tolerations by postgresql manifest
 	if len(*tolerationsSpec) > 0 {
@@ -817,6 +824,7 @@ func (c *Cluster) generatePodTemplate(
 	initContainers []v1.Container,
 	sidecarContainers []v1.Container,
 	sharePgSocketWithSidecars *bool,
+	topologySpreadConstraintsSpec []v1.TopologySpreadConstraint,
 	tolerationsSpec *[]v1.Toleration,
 	nodeAffinity *v1.Affinity,
 	schedulerName *string,
@@ -887,6 +895,8 @@ func (c *Cluster) generatePodTemplate(
 		podSpec.PriorityClassName = priorityClassName
 	}
 
+	podSpec.TopologySpreadConstraints = generateTopologySpreadConstraints(labels, topologySpreadConstraintsSpec)
+
 	if sharePgSocketWithSidecars != nil && *sharePgSocketWithSidecars {
 		addVarRunVolume(&podSpec)
 	}
@@ -1469,6 +1479,7 @@ func (c *Cluster) generateStatefulSet(spec *acidv1.PostgresSpec) (*appsv1.Statef
 		initContainers,
 		sidecarContainers,
 		c.OpConfig.SharePgSocketWithSidecars,
+		spec.TopologySpreadConstraints,
 		&tolerationSpec,
 		c.nodeAffinity(c.OpConfig.NodeReadinessLabel, spec.NodeAffinity),
 		spec.SchedulerName,
@@ -2346,6 +2357,8 @@ func (c *Cluster) generateLogicalBackupJob() (*batchv1.CronJob, error) {
 
 	tolerationsSpec := tolerations(&spec.Tolerations, c.OpConfig.PodToleration)
 
+	topologySpreadConstraintsSpec := generateTopologySpreadConstraints(labels, spec.TopologySpreadConstraints)
+
 	// re-use the method that generates DB pod templates
 	if podTemplate, err = c.generatePodTemplate(
 		c.Namespace,
@@ -2355,6 +2368,7 @@ func (c *Cluster) generateLogicalBackupJob() (*batchv1.CronJob, error) {
 		[]v1.Container{},
 		[]v1.Container{},
 		util.False(),
+		topologySpreadConstraintsSpec,
 		&tolerationsSpec,
 		c.nodeAffinity(c.OpConfig.NodeReadinessLabel, nil),
 		nil,