update docs and change order in config

docs/reference/operator_parameters.md

@@ -161,6 +161,13 @@ configuration they are grouped under the `kubernetes` key.
   replaced by the cluster name. Only the `{cluster}` placeholders is allowed in
   the template.
 
+* **enable_pod_disruption_budget**
+  if disabled `MinAvailable` in the PDB's spec will be set to `0`. That means
+  the PDB will get created anyway. The PDB is also relaxed when scaling down the
+  Postgres cluster to `"numberOfInstances": 0`. When scaling up or enabling this
+  configuration parameter delete the operator Pod to get the PDB synced. By
+  default PDB is enabled which results in `"MinAvailable": 1`
+
 * **secret_name_template**
   a template for the name of the database user secrets generated by the
   operator. `{username}` is replaced with name of the secret, `{cluster}` with

manifests/postgresql-operator-default-configuration.yaml

@@ -20,6 +20,7 @@ configuration:
     pod_service_account_name: operator
     pod_terminate_grace_period: 5m
     pdb_name_format: "postgres-{cluster}-pdb"
+    enable_pod_disruption_budget: true
     secret_name_template: "{username}.{cluster}.credentials.{tprkind}.{tprgroup}"
     cluster_domain: cluster.local
     oauth_token_secret_name: postgresql-operator
@@ -40,7 +41,6 @@ configuration:
     pod_management_policy: "ordered_ready"
     enable_pod_antiaffinity: false
     pod_antiaffinity_topology_key: "kubernetes.io/hostname"
-    enable_pod_disruption_budget: true
   postgres_pod_resources:
     default_cpu_request: 100m
     default_memory_request: 100Mi

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

@@ -49,6 +49,7 @@ type KubernetesMetaConfiguration struct {
 	SpiloFSGroup                           *int64                `json:"spilo_fsgroup,omitempty"`
 	WatchedNamespace                       string                `json:"watched_namespace,omitempty"`
 	PDBNameFormat                          config.StringTemplate `json:"pdb_name_format,omitempty"`
+	EnablePodDisruptionBudget              *bool                 `json:"enable_pod_disruption_budget,omitempty"`
 	SecretNameTemplate                     config.StringTemplate `json:"secret_name_template,omitempty"`
 	ClusterDomain                          string                `json:"cluster_domain"`
 	OAuthTokenSecretName                   spec.NamespacedName   `json:"oauth_token_secret_name,omitempty"`
@@ -67,7 +68,6 @@ type KubernetesMetaConfiguration struct {
 	EnablePodAntiAffinity      bool          `json:"enable_pod_antiaffinity,omitempty"`
 	PodAntiAffinityTopologyKey string        `json:"pod_antiaffinity_topology_key,omitempty"`
 	PodManagementPolicy        string        `json:"pod_management_policy,omitempty"`
-	EnablePodDisruptionBudget  bool          `json:"enable_pod_disruption_budget,omitempty"`
 }
 
 // PostgresPodResourcesDefaults defines the spec of default resources

pkg/cluster/k8sres.go

@@ -1273,9 +1273,10 @@ func (c *Cluster) generateCloneEnvironment(description *acidv1.CloneDescription)
 
 func (c *Cluster) generatePodDisruptionBudget() *policybeta1.PodDisruptionBudget {
 	minAvailable := intstr.FromInt(1)
+	pdbEnabled := c.OpConfig.EnablePodDisruptionBudget
 
 	// Is PodDisruptionBudget is disabled or if there is no master, set the budget to 0.
-	if (c.OpConfig.EnablePodDisruptionBudget != nil && !*c.OpConfig.EnablePodDisruptionBudget) || c.Spec.NumberOfInstances <= 0 {
+	if (pdbEnabled != nil && !*pdbEnabled) || c.Spec.NumberOfInstances <= 0 {
 		minAvailable = intstr.FromInt(0)
 	}
 

pkg/controller/operator_config.go

@@ -41,12 +41,12 @@ func (c *Controller) importConfigurationFromCRD(fromCRD *acidv1.OperatorConfigur
 	result.PodServiceAccountRoleBindingDefinition = fromCRD.Kubernetes.PodServiceAccountRoleBindingDefinition
 	result.PodEnvironmentConfigMap = fromCRD.Kubernetes.PodEnvironmentConfigMap
 	result.PodTerminateGracePeriod = time.Duration(fromCRD.Kubernetes.PodTerminateGracePeriod)
-	result.EnablePodDisruptionBudget = fromCRD.Kubernetes.EnablePodDisruptionBudget
 	result.SpiloPrivileged = fromCRD.Kubernetes.SpiloPrivileged
 	result.SpiloFSGroup = fromCRD.Kubernetes.SpiloFSGroup
 	result.ClusterDomain = fromCRD.Kubernetes.ClusterDomain
 	result.WatchedNamespace = fromCRD.Kubernetes.WatchedNamespace
 	result.PDBNameFormat = fromCRD.Kubernetes.PDBNameFormat
+	result.EnablePodDisruptionBudget = fromCRD.Kubernetes.EnablePodDisruptionBudget
 	result.SecretNameTemplate = fromCRD.Kubernetes.SecretNameTemplate
 	result.OAuthTokenSecretName = fromCRD.Kubernetes.OAuthTokenSecretName
 	result.InfrastructureRolesSecretName = fromCRD.Kubernetes.InfrastructureRolesSecretName

pkg/util/config/config.go

@@ -114,6 +114,7 @@ type Config struct {
 	MasterDNSNameFormat       StringTemplate    `name:"master_dns_name_format" default:"{cluster}.{team}.{hostedzone}"`
 	ReplicaDNSNameFormat      StringTemplate    `name:"replica_dns_name_format" default:"{cluster}-repl.{team}.{hostedzone}"`
 	PDBNameFormat             StringTemplate    `name:"pdb_name_format" default:"postgres-{cluster}-pdb"`
+	EnablePodDisruptionBudget *bool             `name:"enable_pod_disruption_budget" default:"true"`
 	Workers                   uint32            `name:"workers" default:"4"`
 	APIPort                   int               `name:"api_port" default:"8080"`
 	RingLogLines              int               `name:"ring_log_lines" default:"100"`
@@ -121,7 +122,6 @@ type Config struct {
 	TeamAPIRoleConfiguration  map[string]string `name:"team_api_role_configuration" default:"log_statement:all"`
 	PodTerminateGracePeriod   time.Duration     `name:"pod_terminate_grace_period" default:"5m"`
 	PodManagementPolicy       string            `name:"pod_management_policy" default:"ordered_ready"`
-	EnablePodDisruptionBudget *bool             `name:"enable_pod_disruption_budget" default:"true"`
 	ProtectedRoles            []string          `name:"protected_role_names" default:"admin"`
 	PostgresSuperuserTeams    []string          `name:"postgres_superuser_teams" default:""`
 	SetMemoryRequestToLimit   bool              `name:"set_memory_request_to_limit" default:"false"`