Add topologySpreadConstraints configuration to pod spec.

Author: laiminhtrung1997

manifests/postgresql.crd.yaml

@@ -575,6 +575,12 @@ spec:
                         - PreferNoSchedule
                     tolerationSeconds:
                       type: integer
+              topologySpreadConstraints:
+                type: array
+                nullable: true
+                items:
+                  type: object
+                  x-kubernetes-preserve-unknown-fields: true
               useLoadBalancer:
                 type: boolean
                 description: deprecated

pkg/apis/acid.zalan.do/v1/crds.go

@@ -898,6 +898,16 @@ var PostgresCRDResourceValidation = apiextv1.CustomResourceValidation{
 							},
 						},
 					},
+					"topologySpreadConstraints": {
+						Type:     "array",
+						Nullable: true,
+						Items: &apiextv1.JSONSchemaPropsOrArray{
+							Schema: &apiextv1.JSONSchemaProps{
+								Type:                   "object",
+								XPreserveUnknownFields: util.True(),
+							},
+						},
+					},
 					"useLoadBalancer": {
 						Type:        "boolean",
 						Description: "deprecated",

pkg/apis/acid.zalan.do/v1/operator_configuration_type.go

@@ -107,6 +107,7 @@ type KubernetesMetaConfiguration struct {
 	EnableReadinessProbe                     bool                `json:"enable_readiness_probe,omitempty"`
 	EnableCrossNamespaceSecret               bool                `json:"enable_cross_namespace_secret,omitempty"`
 	EnableFinalizers                         *bool               `json:"enable_finalizers,omitempty"`
+	EnablePostgresTopologySpreadConstraints  bool                `json:"enable_postgres_topology_spread_constraints,omitempty"`
 }
 
 // PostgresPodResourcesDefaults defines the spec of default resources

pkg/apis/acid.zalan.do/v1/postgresql_type.go

@@ -93,6 +93,8 @@ type PostgresSpec struct {
 	// deprecated json tags
 	InitContainersOld       []v1.Container `json:"init_containers,omitempty"`
 	PodPriorityClassNameOld string         `json:"pod_priority_class_name,omitempty"`
+
+	AdditionalTopologySpreadConstraints []v1.TopologySpreadConstraint `json:"additionalTopologySpreadConstraints,omitempty"`
 }
 
 // +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object

pkg/cluster/cluster.go

@@ -472,6 +472,11 @@ func (c *Cluster) compareStatefulSetWith(statefulSet *appsv1.StatefulSet) *compa
 		needsRollUpdate = true
 		reasons = append(reasons, "new statefulset's pod affinity does not match the current one")
 	}
+	if !reflect.DeepEqual(c.Statefulset.Spec.Template.Spec.TopologySpreadConstraints, statefulSet.Spec.Template.Spec.TopologySpreadConstraints) {
+		needsReplace = true
+		needsRollUpdate = true
+		reasons = append(reasons, "new statefulset's pod topologySpreadConstraints does not match the current one")
+	}
 	if len(c.Statefulset.Spec.Template.Spec.Tolerations) != len(statefulSet.Spec.Template.Spec.Tolerations) {
 		needsReplace = true
 		needsRollUpdate = true

pkg/cluster/k8sres.go

@@ -610,6 +610,22 @@ func generatePodAntiAffinity(podAffinityTerm v1.PodAffinityTerm, preferredDuring
 	return podAntiAffinity
 }
 
+func generateTopologySpreadConstraints(labels labels.Set, additionalTopologySpreadConstraints []v1.TopologySpreadConstraint) []v1.TopologySpreadConstraint {
+	topologySpreadConstraint := v1.TopologySpreadConstraint{
+		MaxSkew:           int32(1),
+		TopologyKey:       "topology.kubernetes.io/zone",
+		WhenUnsatisfiable: v1.DoNotSchedule,
+		LabelSelector: &metav1.LabelSelector{
+			MatchLabels: labels,
+		},
+	}
+	topologySpreadConstraints := []v1.TopologySpreadConstraint{topologySpreadConstraint}
+	if len(additionalTopologySpreadConstraints) > 0 {
+		topologySpreadConstraints = append(topologySpreadConstraints, additionalTopologySpreadConstraints...)
+	}
+	return topologySpreadConstraints
+}
+
 func tolerations(tolerationsSpec *[]v1.Toleration, podToleration map[string]string) []v1.Toleration {
 	// allow to override tolerations by postgresql manifest
 	if len(*tolerationsSpec) > 0 {
@@ -832,6 +848,8 @@ func (c *Cluster) generatePodTemplate(
 	additionalSecretMount string,
 	additionalSecretMountPath string,
 	additionalVolumes []acidv1.AdditionalVolume,
+	topologySpreadConstraints bool,
+	additionalTopologySpreadConstraints []v1.TopologySpreadConstraint,
 ) (*v1.PodTemplateSpec, error) {
 
 	terminateGracePeriodSeconds := terminateGracePeriod
@@ -884,6 +902,10 @@ func (c *Cluster) generatePodTemplate(
 		podSpec.PriorityClassName = priorityClassName
 	}
 
+	if topologySpreadConstraints {
+		podSpec.TopologySpreadConstraints = generateTopologySpreadConstraints(labels, additionalTopologySpreadConstraints)
+	}
+
 	if sharePgSocketWithSidecars != nil && *sharePgSocketWithSidecars {
 		addVarRunVolume(&podSpec)
 	}
@@ -1487,7 +1509,9 @@ func (c *Cluster) generateStatefulSet(spec *acidv1.PostgresSpec) (*appsv1.Statef
 		c.OpConfig.PodAntiAffinityPreferredDuringScheduling,
 		c.OpConfig.AdditionalSecretMount,
 		c.OpConfig.AdditionalSecretMountPath,
-		additionalVolumes)
+		additionalVolumes,
+		c.OpConfig.EnablePostgresTopologySpreadConstraints,
+		spec.AdditionalTopologySpreadConstraints)
 
 	if err != nil {
 		return nil, fmt.Errorf("could not generate pod template: %v", err)
@@ -2334,7 +2358,9 @@ func (c *Cluster) generateLogicalBackupJob() (*batchv1.CronJob, error) {
 		false,
 		c.OpConfig.AdditionalSecretMount,
 		c.OpConfig.AdditionalSecretMountPath,
-		[]acidv1.AdditionalVolume{}); err != nil {
+		[]acidv1.AdditionalVolume{},
+		true,
+		[]v1.TopologySpreadConstraint{}); err != nil {
 		return nil, fmt.Errorf("could not generate pod template for logical backup pod: %v", err)
 	}
 

pkg/cluster/k8sres_test.go

@@ -3795,3 +3795,47 @@ func TestGenerateCapabilities(t *testing.T) {
 		}
 	}
 }
+
+func TestTopologySpreadConstraints(t *testing.T) {
+	clusterName := "acid-test-cluster"
+	namespace := "default"
+
+	pg := acidv1.Postgresql{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      clusterName,
+			Namespace: namespace,
+		},
+		Spec: acidv1.PostgresSpec{
+			NumberOfInstances: 1,
+			Resources: &acidv1.Resources{
+				ResourceRequests: acidv1.ResourceDescription{CPU: k8sutil.StringToPointer("1"), Memory: k8sutil.StringToPointer("10")},
+				ResourceLimits:   acidv1.ResourceDescription{CPU: k8sutil.StringToPointer("1"), Memory: k8sutil.StringToPointer("10")},
+			},
+			Volume: acidv1.Volume{
+				Size: "1G",
+			},
+		},
+	}
+
+	cluster := New(
+		Config{
+			OpConfig: config.Config{
+				PodManagementPolicy:                     "ordered_ready",
+				EnablePostgresTopologySpreadConstraints: true,
+			},
+		}, k8sutil.KubernetesClient{}, acidv1.Postgresql{}, logger, eventRecorder)
+	cluster.Name = clusterName
+	cluster.Namespace = namespace
+	cluster.labelsSet(true)
+
+	s, err := cluster.generateStatefulSet(&pg.Spec)
+	assert.NoError(t, err)
+	assert.Contains(t, s.Spec.Template.Spec.TopologySpreadConstraints, v1.TopologySpreadConstraint{
+		MaxSkew:           int32(1),
+		TopologyKey:       "topology.kubernetes.io/zone",
+		WhenUnsatisfiable: v1.DoNotSchedule,
+		LabelSelector: &metav1.LabelSelector{
+			MatchLabels: cluster.labelsSet(true),
+		},
+	})
+}

pkg/util/config/config.go

@@ -253,6 +253,7 @@ type Config struct {
 	EnableSecretsDeletion                    *bool             `name:"enable_secrets_deletion" default:"true"`
 	EnablePersistentVolumeClaimDeletion      *bool             `name:"enable_persistent_volume_claim_deletion" default:"true"`
 	PersistentVolumeClaimRetentionPolicy     map[string]string `name:"persistent_volume_claim_retention_policy" default:"when_deleted:retain,when_scaled:retain"`
+	EnablePostgresTopologySpreadConstraints  bool              `json:"enable_postgres_topology_spread_constraints,omitempty"`
 }
 
 // MustMarshal marshals the config or panics