add toggle to turn off readiness probes (zalando#2004)

* add toggle to turn off readiness probes
* include PodManagementPolicy and ReadinessProbe in stateful set comparison
* add URI scheme to generated readiness probe

Author: FxKu

charts/postgres-operator/crds/operatorconfigurations.yaml

@@ -214,6 +214,9 @@ spec:
                   enable_pod_disruption_budget:
                     type: boolean
                     default: true
+                  enable_readiness_probe:
+                    type: boolean
+                    default: false
                   enable_sidecars:
                     type: boolean
                     default: true

charts/postgres-operator/values.yaml

@@ -129,6 +129,8 @@ configKubernetes:
   enable_pod_antiaffinity: false
   # toggles PDB to set to MinAvailabe 0 or 1
   enable_pod_disruption_budget: true
+  # toogles readiness probe for database pods
+  enable_readiness_probe: false
   # enables sidecar containers to run alongside Spilo in the same pod
   enable_sidecars: true
 

docs/reference/operator_parameters.md

@@ -489,6 +489,14 @@ configuration they are grouped under the `kubernetes` key.
   of stateful sets of PG clusters. The default is `ordered_ready`, the second
   possible value is `parallel`.
 
+* **enable_readiness_probe**
+  the operator can set a readiness probe on the statefulset for the database
+  pods with `InitialDelaySeconds: 6`, `PeriodSeconds: 10`, `TimeoutSeconds: 5`,
+  `SuccessThreshold: 1` and `FailureThreshold: 3`. When enabling readiness
+  probes it is recommended to switch the `pod_management_policy` to `parallel`
+  to avoid unneccesary waiting times in case of multiple instances failing.
+  The default is `false`.
+
 * **storage_resize_mode**
   defines how operator handles the difference between the requested volume size and
     the actual size. Available options are:

manifests/configmap.yaml

@@ -52,6 +52,7 @@ data:
   # enable_pod_disruption_budget: "true"
   # enable_postgres_team_crd: "false"
   # enable_postgres_team_crd_superusers: "false"
+  enable_readiness_probe: "false"
   enable_replica_load_balancer: "false"
   enable_replica_pooler_load_balancer: "false"
   # enable_shm_volume: "true"

manifests/operatorconfiguration.crd.yaml

@@ -212,6 +212,9 @@ spec:
                   enable_pod_disruption_budget:
                     type: boolean
                     default: true
+                  enable_readiness_probe:
+                    type: boolean
+                    default: false
                   enable_sidecars:
                     type: boolean
                     default: true

manifests/postgresql-operator-default-configuration.yaml

@@ -60,6 +60,7 @@ configuration:
     enable_init_containers: true
     enable_pod_antiaffinity: false
     enable_pod_disruption_budget: true
+    enable_readiness_probe: false
     enable_sidecars: true
     # ignored_annotations:
     # - k8s.v1.cni.cncf.io/network-status

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

@@ -1275,6 +1275,9 @@ var OperatorConfigCRDResourceValidation = apiextv1.CustomResourceValidation{
 							"enable_pod_disruption_budget": {
 								Type: "boolean",
 							},
+							"enable_readiness_probe": {
+								Type: "boolean",
+							},
 							"enable_sidecars": {
 								Type: "boolean",
 							},

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

@@ -98,6 +98,7 @@ 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"`
+	EnableReadinessProbe       bool                `json:"enable_readiness_probe,omitempty"`
 	EnableCrossNamespaceSecret bool                `json:"enable_cross_namespace_secret,omitempty"`
 }
 

pkg/cluster/cluster.go

@@ -389,6 +389,11 @@ func (c *Cluster) compareStatefulSetWith(statefulSet *appsv1.StatefulSet) *compa
 		needsReplace = true
 		reasons = append(reasons, "new statefulset's annotations do not match: "+reason)
 	}
+	if c.Statefulset.Spec.PodManagementPolicy != statefulSet.Spec.PodManagementPolicy {
+		match = false
+		needsReplace = true
+		reasons = append(reasons, "new statefulset's pod management policy do not match")
+	}
 
 	needsRollUpdate, reasons = c.compareContainers("initContainers", c.Statefulset.Spec.Template.Spec.InitContainers, statefulSet.Spec.Template.Spec.InitContainers, needsRollUpdate, reasons)
 	needsRollUpdate, reasons = c.compareContainers("containers", c.Statefulset.Spec.Template.Spec.Containers, statefulSet.Spec.Template.Spec.Containers, needsRollUpdate, reasons)
@@ -528,6 +533,8 @@ func (c *Cluster) compareContainers(description string, setA, setB []v1.Containe
 	checks := []containerCheck{
 		newCheck("new statefulset %s's %s (index %d) name does not match the current one",
 			func(a, b v1.Container) bool { return a.Name != b.Name }),
+		newCheck("new statefulset %s's %s (index %d) readiness probe does not match the current one",
+			func(a, b v1.Container) bool { return !reflect.DeepEqual(a.ReadinessProbe, b.ReadinessProbe) }),
 		newCheck("new statefulset %s's %s (index %d) ports do not match the current one",
 			func(a, b v1.Container) bool { return !comparePorts(a.Ports, b.Ports) }),
 		newCheck("new statefulset %s's %s (index %d) resources do not match the current ones",

pkg/cluster/k8sres.go

@@ -1119,17 +1119,18 @@ func extractPgVersionFromBinPath(binPath string, template string) (string, error
 
 func generateSpiloReadinessProbe() *v1.Probe {
 	return &v1.Probe{
+		FailureThreshold: 3,
 		Handler: v1.Handler{
 			HTTPGet: &v1.HTTPGetAction{
-				Path: "/readiness",
-				Port: intstr.IntOrString{IntVal: patroni.ApiPort},
+				Path:   "/readiness",
+				Port:   intstr.IntOrString{IntVal: patroni.ApiPort},
+				Scheme: v1.URISchemeHTTP,
 			},
 		},
 		InitialDelaySeconds: 6,
 		PeriodSeconds:       10,
-		TimeoutSeconds:      5,
 		SuccessThreshold:    1,
-		FailureThreshold:    3,
+		TimeoutSeconds:      5,
 	}
 }
 
@@ -1280,7 +1281,9 @@ func (c *Cluster) generateStatefulSet(spec *acidv1.PostgresSpec) (*appsv1.Statef
 	)
 
 	// Patroni responds 200 to probe only if it either owns the leader lock or postgres is running and DCS is accessible
-	spiloContainer.ReadinessProbe = generateSpiloReadinessProbe()
+	if c.OpConfig.EnableReadinessProbe {
+		spiloContainer.ReadinessProbe = generateSpiloReadinessProbe()
+	}
 
 	// generate container specs for sidecars specified in the cluster manifest
 	clusterSpecificSidecars := []v1.Container{}