add unit test and documentation for finalizers (#2509)

* add unit test and documentation for finalizers
* error msg with lower case and cover sync case
* try to avoid adding json-patch dependency
* use Update to remove finalizer
* changing status and finalizer during create
* do not call Delete() twice

docs/reference/operator_parameters.md

@@ -328,6 +328,14 @@ configuration they are grouped under the `kubernetes` key.
   drained if the node_readiness_label is not used. This option if set to `false`
   will not add the `spilo-role=master` selector to the PDB.
 
+* **enable_finalizers**
+  By default, a deletion of the Postgresql resource will trigger a cleanup of
+  all child resources. However, if the database cluster is in a broken state
+  (e.g. failed initialization) and the operator cannot fully sync it, there can
+  be leftovers from a DELETE event. By enabling finalizers the Operator will
+  ensure all managed resources are deleted prior to the Postgresql resource.
+  The default is `false`.
+
 * **enable_pod_disruption_budget**
   PDB is enabled by default to protect the cluster from voluntarily disruptions
   and hence unwanted DB downtime. However, on some cloud providers it could be

pkg/cluster/cluster.go

@@ -13,7 +13,6 @@ import (
 	"sync"
 	"time"
 
-	jsonpatch "github.com/evanphx/json-patch"
 	"github.com/sirupsen/logrus"
 	acidv1 "github.com/zalando/postgres-operator/pkg/apis/acid.zalan.do/v1"
 
@@ -248,6 +247,7 @@ func (c *Cluster) Create() (err error) {
 	defer c.mu.Unlock()
 
 	var (
+		pgCreateStatus *acidv1.Postgresql
 		service        *v1.Service
 		ep             *v1.Endpoints
 		ss             *appsv1.StatefulSet
@@ -261,11 +261,15 @@ func (c *Cluster) Create() (err error) {
 		}
 	}()
 
-	c.KubeClient.SetPostgresCRDStatus(c.clusterName(), acidv1.ClusterStatusCreating)
+	pgCreateStatus, err = c.KubeClient.SetPostgresCRDStatus(c.clusterName(), acidv1.ClusterStatusCreating)
+	if err != nil {
+		return fmt.Errorf("could not set cluster status: %v", err)
+	}
+	c.setSpec(pgCreateStatus)
+
 	if c.OpConfig.EnableFinalizers != nil && *c.OpConfig.EnableFinalizers {
-		c.logger.Info("Adding finalizer.")
+		if err = c.addFinalizer(); err != nil {
-		if err = c.AddFinalizer(); err != nil {
+			return fmt.Errorf("could not add finalizer: %v", err)
-			return fmt.Errorf("could not add Finalizer: %v", err)
 		}
 	}
 	c.eventRecorder.Event(c.GetReference(), v1.EventTypeNormal, "Create", "Started creation of new cluster resources")
@@ -771,60 +775,45 @@ func (c *Cluster) compareServices(old, new *v1.Service) (bool, string) {
 	return true, ""
 }
 
-// AddFinalizer patches the postgresql CR to add our finalizer.
+// addFinalizer patches the postgresql CR to add finalizer
-func (c *Cluster) AddFinalizer() error {
+func (c *Cluster) addFinalizer() error {
-	if c.HasFinalizer() {
+	if c.hasFinalizer() {
-		c.logger.Debugf("Finalizer %s already exists.", finalizerName)
 		return nil
 	}
 
-	currentSpec := c.DeepCopy()
+	c.logger.Infof("adding finalizer %s", finalizerName)
-	newSpec := c.DeepCopy()
+	finalizers := append(c.ObjectMeta.Finalizers, finalizerName)
-	newSpec.ObjectMeta.SetFinalizers(append(newSpec.ObjectMeta.Finalizers, finalizerName))
+	newSpec, err := c.KubeClient.SetFinalizer(c.clusterName(), c.DeepCopy(), finalizers)
-	patchBytes, err := getPatchBytes(currentSpec, newSpec)
 	if err != nil {
-		return fmt.Errorf("Unable to produce patch to add finalizer: %v", err)
+		return fmt.Errorf("error adding finalizer: %v", err)
 	}
 
-	updatedSpec, err := c.KubeClient.AcidV1ClientSet.AcidV1().Postgresqls(c.clusterNamespace()).Patch(
+	// update the spec, maintaining the new resourceVersion
-		context.TODO(), c.Name, types.MergePatchType, patchBytes, metav1.PatchOptions{})
+	c.setSpec(newSpec)
-	if err != nil {
-		return fmt.Errorf("Could not add finalizer: %v", err)
-	}
-
-	// update the spec, maintaining the new resourceVersion.
-	c.setSpec(updatedSpec)
 	return nil
 }
 
-// RemoveFinalizer patches postgresql CR to remove finalizer.
+// removeFinalizer patches postgresql CR to remove finalizer
-func (c *Cluster) RemoveFinalizer() error {
+func (c *Cluster) removeFinalizer() error {
-	if !c.HasFinalizer() {
+	if !c.hasFinalizer() {
-		c.logger.Debugf("No finalizer %s exists to remove.", finalizerName)
 		return nil
 	}
-	currentSpec := c.DeepCopy()
-	newSpec := c.DeepCopy()
-	newSpec.ObjectMeta.SetFinalizers(removeString(newSpec.ObjectMeta.Finalizers, finalizerName))
-	patchBytes, err := getPatchBytes(currentSpec, newSpec)
-	if err != nil {
-		return fmt.Errorf("Unable to produce patch to remove finalizer: %v", err)
-	}
 
-	updatedSpec, err := c.KubeClient.AcidV1ClientSet.AcidV1().Postgresqls(c.clusterNamespace()).Patch(
+	c.logger.Infof("removing finalizer %s", finalizerName)
-		context.TODO(), c.Name, types.MergePatchType, patchBytes, metav1.PatchOptions{})
+	finalizers := util.RemoveString(c.ObjectMeta.Finalizers, finalizerName)
+	newSpec, err := c.KubeClient.SetFinalizer(c.clusterName(), c.DeepCopy(), finalizers)
 	if err != nil {
-		return fmt.Errorf("Could not remove finalizer: %v", err)
+		return fmt.Errorf("error removing finalizer: %v", err)
 	}
 
 	// update the spec, maintaining the new resourceVersion.
-	c.setSpec(updatedSpec)
+	c.setSpec(newSpec)
 
 	return nil
 }
 
-// HasFinalizer checks if our finalizer is currently set or not
+// hasFinalizer checks if finalizer is currently set or not
-func (c *Cluster) HasFinalizer() bool {
+func (c *Cluster) hasFinalizer() bool {
 	for _, finalizer := range c.ObjectMeta.Finalizers {
 		if finalizer == finalizerName {
 			return true
@@ -833,36 +822,6 @@ func (c *Cluster) HasFinalizer() bool {
 	return false
 }
 
-// Iterate through slice and remove certain string, then return cleaned slice
-func removeString(slice []string, s string) (result []string) {
-	for _, item := range slice {
-		if item == s {
-			continue
-		}
-		result = append(result, item)
-	}
-	return result
-}
-
-// getPatchBytes will produce a JSONpatch between the two parameters of type acidv1.Postgresql
-func getPatchBytes(oldSpec, newSpec *acidv1.Postgresql) ([]byte, error) {
-	oldData, err := json.Marshal(oldSpec)
-	if err != nil {
-		return nil, fmt.Errorf("failed to Marshal oldSpec for postgresql %s/%s: %v", oldSpec.Namespace, oldSpec.Name, err)
-	}
-
-	newData, err := json.Marshal(newSpec)
-	if err != nil {
-		return nil, fmt.Errorf("failed to Marshal newSpec for postgresql %s/%s: %v", newSpec.Namespace, newSpec.Name, err)
-	}
-
-	patchBytes, err := jsonpatch.CreateMergePatch(oldData, newData)
-	if err != nil {
-		return nil, fmt.Errorf("failed to CreateMergePatch for postgresl %s/%s: %v", oldSpec.Namespace, oldSpec.Name, err)
-	}
-	return patchBytes, nil
-}
-
 // Update changes Kubernetes objects according to the new specification. Unlike the sync case, the missing object
 // (i.e. service) is treated as an error
 // logical backup cron jobs are an exception: a user-initiated Update can enable a logical backup job
@@ -1106,40 +1065,41 @@ func syncResources(a, b *v1.ResourceRequirements) bool {
 // before the pods, it will be re-created by the current master pod and will remain, obstructing the
 // creation of the new cluster with the same name. Therefore, the endpoints should be deleted last.
 func (c *Cluster) Delete() error {
+	var anyErrors = false
 	c.mu.Lock()
 	defer c.mu.Unlock()
 	c.eventRecorder.Event(c.GetReference(), v1.EventTypeNormal, "Delete", "Started deletion of cluster resources")
 
 	if err := c.deleteStreams(); err != nil {
+		anyErrors = true
 		c.logger.Warningf("could not delete event streams: %v", err)
-		c.eventRecorder.Eventf(c.GetReference(), v1.EventTypeWarning, "Delete", "Could not delete event streams: %v", err)
+		c.eventRecorder.Eventf(c.GetReference(), v1.EventTypeWarning, "Delete", "could not delete event streams: %v", err)
 	}
-	var anyErrors = false
 
 	// delete the backup job before the stateful set of the cluster to prevent connections to non-existing pods
 	// deleting the cron job also removes pods and batch jobs it created
 	if err := c.deleteLogicalBackupJob(); err != nil {
 		anyErrors = true
 		c.logger.Warningf("could not remove the logical backup k8s cron job; %v", err)
-		c.eventRecorder.Eventf(c.GetReference(), v1.EventTypeWarning, "Delete", "Could not remove the logical backup k8s cron job; %v", err)
+		c.eventRecorder.Eventf(c.GetReference(), v1.EventTypeWarning, "Delete", "could not remove the logical backup k8s cron job; %v", err)
 	}
 
 	if err := c.deleteStatefulSet(); err != nil {
 		anyErrors = true
 		c.logger.Warningf("could not delete statefulset: %v", err)
-		c.eventRecorder.Eventf(c.GetReference(), v1.EventTypeWarning, "Delete", "Could not delete statefulset: %v", err)
+		c.eventRecorder.Eventf(c.GetReference(), v1.EventTypeWarning, "Delete", "could not delete statefulset: %v", err)
 	}
 
 	if err := c.deleteSecrets(); err != nil {
 		anyErrors = true
 		c.logger.Warningf("could not delete secrets: %v", err)
-		c.eventRecorder.Eventf(c.GetReference(), v1.EventTypeWarning, "Delete", "Could not delete secrets: %v", err)
+		c.eventRecorder.Eventf(c.GetReference(), v1.EventTypeWarning, "Delete", "could not delete secrets: %v", err)
 	}
 
 	if err := c.deletePodDisruptionBudget(); err != nil {
 		anyErrors = true
 		c.logger.Warningf("could not delete pod disruption budget: %v", err)
-		c.eventRecorder.Eventf(c.GetReference(), v1.EventTypeWarning, "Delete", "Could not delete pod disruption budget: %v", err)
+		c.eventRecorder.Eventf(c.GetReference(), v1.EventTypeWarning, "Delete", "could not delete pod disruption budget: %v", err)
 	}
 
 	for _, role := range []PostgresRole{Master, Replica} {
@@ -1148,21 +1108,21 @@ func (c *Cluster) Delete() error {
 			if err := c.deleteEndpoint(role); err != nil {
 				anyErrors = true
 				c.logger.Warningf("could not delete %s endpoint: %v", role, err)
-				c.eventRecorder.Eventf(c.GetReference(), v1.EventTypeWarning, "Delete", "Could not delete %s endpoint: %v", role, err)
+				c.eventRecorder.Eventf(c.GetReference(), v1.EventTypeWarning, "Delete", "could not delete %s endpoint: %v", role, err)
 			}
 		}
 
 		if err := c.deleteService(role); err != nil {
 			anyErrors = true
 			c.logger.Warningf("could not delete %s service: %v", role, err)
-			c.eventRecorder.Eventf(c.GetReference(), v1.EventTypeWarning, "Delete", "Could not delete %s service: %v", role, err)
+			c.eventRecorder.Eventf(c.GetReference(), v1.EventTypeWarning, "Delete", "could not delete %s service: %v", role, err)
 		}
 	}
 
 	if err := c.deletePatroniClusterObjects(); err != nil {
 		anyErrors = true
 		c.logger.Warningf("could not remove leftover patroni objects; %v", err)
-		c.eventRecorder.Eventf(c.GetReference(), v1.EventTypeWarning, "Delete", "Could not remove leftover patroni objects; %v", err)
+		c.eventRecorder.Eventf(c.GetReference(), v1.EventTypeWarning, "Delete", "could not remove leftover patroni objects; %v", err)
 	}
 
 	// Delete connection pooler objects anyway, even if it's not mentioned in the
@@ -1172,20 +1132,19 @@ func (c *Cluster) Delete() error {
 		if err := c.deleteConnectionPooler(role); err != nil {
 			anyErrors = true
 			c.logger.Warningf("could not remove connection pooler: %v", err)
-			c.eventRecorder.Eventf(c.GetReference(), v1.EventTypeWarning, "Delete", "Could not remove connection pooler: %v", err)
+			c.eventRecorder.Eventf(c.GetReference(), v1.EventTypeWarning, "Delete", "could not remove connection pooler: %v", err)
 		}
 	}
 
 	// If we are done deleting our various resources we remove the finalizer to let K8S finally delete the Postgres CR
 	if anyErrors {
-		c.eventRecorder.Event(c.GetReference(), v1.EventTypeWarning, "Delete", "Some resources could be successfully deleted yet")
+		c.eventRecorder.Event(c.GetReference(), v1.EventTypeWarning, "Delete", "some resources could be successfully deleted yet")
 		return fmt.Errorf("some error(s) occured when deleting resources, NOT removing finalizer yet")
 	}
-	if err := c.RemoveFinalizer(); err != nil {
+	if err := c.removeFinalizer(); err != nil {
-		return fmt.Errorf("Done cleaning up, but error when trying to remove our finalizer: %v", err)
+		return fmt.Errorf("done cleaning up, but error when removing finalizer: %v", err)
 	}
 
-	c.logger.Info("Done cleaning up our resources, removed finalizer.")
 	return nil
 }
 

pkg/cluster/cluster_test.go

@@ -1,11 +1,13 @@
 package cluster
 
 import (
+	"context"
 	"fmt"
 	"net/http"
 	"reflect"
 	"strings"
 	"testing"
+	"time"
 
 	"github.com/sirupsen/logrus"
 	"github.com/stretchr/testify/assert"
@@ -33,7 +35,10 @@ const (
 )
 
 var logger = logrus.New().WithField("test", "cluster")
-var eventRecorder = record.NewFakeRecorder(1)
+
+// eventRecorder needs buffer for TestCreate which emit events for
+// 1 cluster, primary endpoint, 2 services, the secrets, the statefulset and pods being ready
+var eventRecorder = record.NewFakeRecorder(7)
 
 var cl = New(
 	Config{
@@ -79,6 +84,79 @@ var cl = New(
 	eventRecorder,
 )
 
+func TestCreate(t *testing.T) {
+	clientSet := fake.NewSimpleClientset()
+	acidClientSet := fakeacidv1.NewSimpleClientset()
+	clusterName := "cluster-with-finalizer"
+	clusterNamespace := "test"
+
+	client := k8sutil.KubernetesClient{
+		DeploymentsGetter:            clientSet.AppsV1(),
+		EndpointsGetter:              clientSet.CoreV1(),
+		PersistentVolumeClaimsGetter: clientSet.CoreV1(),
+		PodDisruptionBudgetsGetter:   clientSet.PolicyV1(),
+		PodsGetter:                   clientSet.CoreV1(),
+		PostgresqlsGetter:            acidClientSet.AcidV1(),
+		ServicesGetter:               clientSet.CoreV1(),
+		SecretsGetter:                clientSet.CoreV1(),
+		StatefulSetsGetter:           clientSet.AppsV1(),
+	}
+
+	pg := acidv1.Postgresql{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      clusterName,
+			Namespace: clusterNamespace,
+		},
+		Spec: acidv1.PostgresSpec{
+			Volume: acidv1.Volume{
+				Size: "1Gi",
+			},
+		},
+	}
+
+	pod := v1.Pod{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      fmt.Sprintf("%s-0", clusterName),
+			Namespace: clusterNamespace,
+			Labels: map[string]string{
+				"application":  "spilo",
+				"cluster-name": clusterName,
+				"spilo-role":   "master",
+			},
+		},
+	}
+
+	// manually create resources which must be found by further API calls and are not created by cluster.Create()
+	client.Postgresqls(clusterNamespace).Create(context.TODO(), &pg, metav1.CreateOptions{})
+	client.Pods(clusterNamespace).Create(context.TODO(), &pod, metav1.CreateOptions{})
+
+	var cluster = New(
+		Config{
+			OpConfig: config.Config{
+				PodManagementPolicy: "ordered_ready",
+				Resources: config.Resources{
+					ClusterLabels:         map[string]string{"application": "spilo"},
+					ClusterNameLabel:      "cluster-name",
+					DefaultCPURequest:     "300m",
+					DefaultCPULimit:       "300m",
+					DefaultMemoryRequest:  "300Mi",
+					DefaultMemoryLimit:    "300Mi",
+					PodRoleLabel:          "spilo-role",
+					ResourceCheckInterval: time.Duration(3),
+					ResourceCheckTimeout:  time.Duration(10),
+				},
+				EnableFinalizers: util.True(),
+			},
+		}, client, pg, logger, eventRecorder)
+
+	err := cluster.Create()
+	assert.NoError(t, err)
+
+	if !cluster.hasFinalizer() {
+		t.Errorf("%s - expected finalizer not found on cluster", t.Name())
+	}
+}
+
 func TestStatefulSetAnnotations(t *testing.T) {
 	spec := acidv1.PostgresSpec{
 		TeamID: "myapp", NumberOfInstances: 1,

pkg/cluster/connection_pooler.go

@@ -610,7 +610,7 @@ func (c *Cluster) deleteConnectionPooler(role PostgresRole) (err error) {
 			Delete(context.TODO(), deployment.Name, options)
 
 		if k8sutil.ResourceNotFound(err) {
-			c.logger.Debugf("connection pooler deployment was already deleted")
+			c.logger.Debugf("connection pooler deployment %s for role %s has already been deleted", deployment.Name, role)
 		} else if err != nil {
 			return fmt.Errorf("could not delete connection pooler deployment: %v", err)
 		}
@@ -629,7 +629,7 @@ func (c *Cluster) deleteConnectionPooler(role PostgresRole) (err error) {
 			Delete(context.TODO(), service.Name, options)
 
 		if k8sutil.ResourceNotFound(err) {
-			c.logger.Debugf("connection pooler service was already deleted")
+			c.logger.Debugf("connection pooler service %s for role %s has already been already deleted", service.Name, role)
 		} else if err != nil {
 			return fmt.Errorf("could not delete connection pooler service: %v", err)
 		}

pkg/cluster/k8sres_test.go

@@ -2741,7 +2741,7 @@ func TestGenerateResourceRequirements(t *testing.T) {
 	clusterNameLabel := "cluster-name"
 	sidecarName := "postgres-exporter"
 
-	// enforceMinResourceLimits will be called 2 twice emitting 4 events (2x cpu, 2x memory raise)
+	// enforceMinResourceLimits will be called 2 times emitting 4 events (2x cpu, 2x memory raise)
 	// enforceMaxResourceRequests will be called 4 times emitting 6 events (2x cpu, 4x memory cap)
 	// hence event bufferSize of 10 is required
 	newEventRecorder := record.NewFakeRecorder(10)

pkg/cluster/majorversionupgrade.go

@@ -17,7 +17,6 @@ var VersionMap = map[string]int{
 	"13": 130000,
 	"14": 140000,
 	"15": 150000,
-
 }
 
 // IsBiggerPostgresVersion Compare two Postgres version numbers
@@ -104,31 +103,31 @@ func (c *Cluster) majorVersionUpgrade() error {
 		if c.currentMajorVersion < desiredVersion {
 			podName := &spec.NamespacedName{Namespace: masterPod.Namespace, Name: masterPod.Name}
 			c.logger.Infof("triggering major version upgrade on pod %s of %d pods", masterPod.Name, numberOfPods)
-			c.eventRecorder.Eventf(c.GetReference(), v1.EventTypeNormal, "Major Version Upgrade", "Starting major version upgrade on pod %s of %d pods", masterPod.Name, numberOfPods)
+			c.eventRecorder.Eventf(c.GetReference(), v1.EventTypeNormal, "Major Version Upgrade", "starting major version upgrade on pod %s of %d pods", masterPod.Name, numberOfPods)
 			upgradeCommand := fmt.Sprintf("set -o pipefail && /usr/bin/python3 /scripts/inplace_upgrade.py %d 2>&1 | tee last_upgrade.log", numberOfPods)
 
 			c.logger.Debugf("checking if the spilo image runs with root or non-root (check for user id=0)")
 			resultIdCheck, errIdCheck := c.ExecCommand(podName, "/bin/bash", "-c", "/usr/bin/id -u")
 			if errIdCheck != nil {
-				c.eventRecorder.Eventf(c.GetReference(), v1.EventTypeWarning, "Major Version Upgrade", "Checking user id to run upgrade from %d to %d FAILED: %v", c.currentMajorVersion, desiredVersion, errIdCheck)
+				c.eventRecorder.Eventf(c.GetReference(), v1.EventTypeWarning, "Major Version Upgrade", "checking user id to run upgrade from %d to %d FAILED: %v", c.currentMajorVersion, desiredVersion, errIdCheck)
 			}
 
 			resultIdCheck = strings.TrimSuffix(resultIdCheck, "\n")
 			var result string
 			if resultIdCheck != "0" {
-				c.logger.Infof("User id was identified as: %s, hence default user is non-root already", resultIdCheck)
+				c.logger.Infof("user id was identified as: %s, hence default user is non-root already", resultIdCheck)
 				result, err = c.ExecCommand(podName, "/bin/bash", "-c", upgradeCommand)
 			} else {
-				c.logger.Infof("User id was identified as: %s, using su to reach the postgres user", resultIdCheck)
+				c.logger.Infof("user id was identified as: %s, using su to reach the postgres user", resultIdCheck)
 				result, err = c.ExecCommand(podName, "/bin/su", "postgres", "-c", upgradeCommand)
 			}
 			if err != nil {
-				c.eventRecorder.Eventf(c.GetReference(), v1.EventTypeWarning, "Major Version Upgrade", "Upgrade from %d to %d FAILED: %v", c.currentMajorVersion, desiredVersion, err)
+				c.eventRecorder.Eventf(c.GetReference(), v1.EventTypeWarning, "Major Version Upgrade", "upgrade from %d to %d FAILED: %v", c.currentMajorVersion, desiredVersion, err)
 				return err
 			}
 			c.logger.Infof("upgrade action triggered and command completed: %s", result[:100])
 
-			c.eventRecorder.Eventf(c.GetReference(), v1.EventTypeNormal, "Major Version Upgrade", "Upgrade from %d to %d finished", c.currentMajorVersion, desiredVersion)
+			c.eventRecorder.Eventf(c.GetReference(), v1.EventTypeNormal, "Major Version Upgrade", "upgrade from %d to %d finished", c.currentMajorVersion, desiredVersion)
 		}
 	}
 

pkg/cluster/resources.go

@@ -248,7 +248,7 @@ func (c *Cluster) deleteStatefulSet() error {
 
 	err := c.KubeClient.StatefulSets(c.Statefulset.Namespace).Delete(context.TODO(), c.Statefulset.Name, c.deleteOptions)
 	if k8sutil.ResourceNotFound(err) {
-		c.logger.Debugf("StatefulSet was already deleted")
+		c.logger.Debugf("statefulset %q has already been deleted", util.NameFromMeta(c.Statefulset.ObjectMeta))
 	} else if err != nil {
 		return err
 	}
@@ -346,7 +346,7 @@ func (c *Cluster) deleteService(role PostgresRole) error {
 
 	if err := c.KubeClient.Services(c.Services[role].Namespace).Delete(context.TODO(), c.Services[role].Name, c.deleteOptions); err != nil {
 		if k8sutil.ResourceNotFound(err) {
-			c.logger.Debugf("Service was already deleted")
+			c.logger.Debugf("%s service has already been deleted", role)
 		} else if err != nil {
 			return err
 		}
@@ -455,7 +455,7 @@ func (c *Cluster) deletePodDisruptionBudget() error {
 		PodDisruptionBudgets(c.PodDisruptionBudget.Namespace).
 		Delete(context.TODO(), c.PodDisruptionBudget.Name, c.deleteOptions)
 	if k8sutil.ResourceNotFound(err) {
-		c.logger.Debugf("PodDisruptionBudget was already deleted")
+		c.logger.Debugf("PodDisruptionBudget %q has already been deleted", util.NameFromMeta(c.PodDisruptionBudget.ObjectMeta))
 	} else if err != nil {
 		return fmt.Errorf("could not delete PodDisruptionBudget: %v", err)
 	}
@@ -490,13 +490,13 @@ func (c *Cluster) deleteEndpoint(role PostgresRole) error {
 
 	if err := c.KubeClient.Endpoints(c.Endpoints[role].Namespace).Delete(context.TODO(), c.Endpoints[role].Name, c.deleteOptions); err != nil {
 		if k8sutil.ResourceNotFound(err) {
-			c.logger.Debugf("Endpoint was already deleted")
+			c.logger.Debugf("%s endpoint has already been deleted", role)
 		} else if err != nil {
 			return fmt.Errorf("could not delete endpoint: %v", err)
 		}
 	}
 
-	c.logger.Infof("endpoint %q has been deleted", util.NameFromMeta(c.Endpoints[role].ObjectMeta))
+	c.logger.Infof("%s endpoint %q has been deleted", role, util.NameFromMeta(c.Endpoints[role].ObjectMeta))
 	delete(c.Endpoints, role)
 
 	return nil
@@ -526,7 +526,7 @@ func (c *Cluster) deleteSecret(uid types.UID, secret v1.Secret) error {
 	c.logger.Debugf("deleting secret %q", secretName)
 	err := c.KubeClient.Secrets(secret.Namespace).Delete(context.TODO(), secret.Name, c.deleteOptions)
 	if k8sutil.ResourceNotFound(err) {
-		c.logger.Debugf("Secret was already deleted")
+		c.logger.Debugf("secret %q has already been deleted", secretName)
 	} else if err != nil {
 		return fmt.Errorf("could not delete secret %q: %v", secretName, err)
 	}
@@ -588,7 +588,7 @@ func (c *Cluster) deleteLogicalBackupJob() error {
 
 	err := c.KubeClient.CronJobsGetter.CronJobs(c.Namespace).Delete(context.TODO(), c.getLogicalBackupJobName(), c.deleteOptions)
 	if k8sutil.ResourceNotFound(err) {
-		c.logger.Debugf("LogicalBackup CronJob was already deleted")
+		c.logger.Debugf("logical backup cron job %q has already been deleted", c.getLogicalBackupJobName())
 	} else if err != nil {
 		return err
 	}

pkg/cluster/sync.go

@@ -48,6 +48,10 @@ func (c *Cluster) Sync(newSpec *acidv1.Postgresql) error {
 		}
 	}()
 
+	if err = c.syncFinalizer(); err != nil {
+		c.logger.Debugf("could not sync finalizers: %v", err)
+	}
+
 	if err = c.initUsers(); err != nil {
 		err = fmt.Errorf("could not init users: %v", err)
 		return err
@@ -144,6 +148,20 @@ func (c *Cluster) Sync(newSpec *acidv1.Postgresql) error {
 	return err
 }
 
+func (c *Cluster) syncFinalizer() error {
+	var err error
+	if c.OpConfig.EnableFinalizers != nil && *c.OpConfig.EnableFinalizers {
+		err = c.addFinalizer()
+	} else {
+		err = c.removeFinalizer()
+	}
+	if err != nil {
+		return fmt.Errorf("could not sync finalizer: %v", err)
+	}
+
+	return nil
+}
+
 func (c *Cluster) syncServices() error {
 	for _, role := range []PostgresRole{Master, Replica} {
 		c.logger.Debugf("syncing %s service", role)

pkg/controller/postgresql.go

@@ -285,15 +285,18 @@ func (c *Controller) processEvent(event ClusterEvent) {
 			lg.Errorf("unknown cluster: %q", clusterName)
 			return
 		}
-		lg.Infoln("deletion of the cluster started")
 
 		teamName := strings.ToLower(cl.Spec.TeamID)
-
 		c.curWorkerCluster.Store(event.WorkerID, cl)
+
+		// when using finalizers the deletion already happened
+		if c.opConfig.EnableFinalizers == nil || !*c.opConfig.EnableFinalizers {
+			lg.Infoln("deletion of the cluster started")
 			if err := cl.Delete(); err != nil {
-			cl.Error = fmt.Sprintf("Could not delete cluster: %v", err)
+				cl.Error = fmt.Sprintf("could not delete cluster: %v", err)
 				c.eventRecorder.Eventf(cl.GetReference(), v1.EventTypeWarning, "Delete", "%v", cl.Error)
 			}
+		}
 
 		func() {
 			defer c.clustersMu.Unlock()
@@ -329,9 +332,9 @@ func (c *Controller) processEvent(event ClusterEvent) {
 
 		// has this cluster been marked as deleted already, then we shall start cleaning up
 		if !cl.ObjectMeta.DeletionTimestamp.IsZero() {
-			lg.Infof("Cluster has a DeletionTimestamp of %s, starting deletion now.", cl.ObjectMeta.DeletionTimestamp.Format(time.RFC3339))
+			lg.Infof("cluster has a DeletionTimestamp of %s, starting deletion now.", cl.ObjectMeta.DeletionTimestamp.Format(time.RFC3339))
 			if err = cl.Delete(); err != nil {
-				cl.Error = fmt.Sprintf("Error deleting cluster and its resources: %v", err)
+				cl.Error = fmt.Sprintf("error deleting cluster and its resources: %v", err)
 				c.eventRecorder.Eventf(cl.GetReference(), v1.EventTypeWarning, "Delete", "%v", cl.Error)
 				lg.Error(cl.Error)
 				return
@@ -572,13 +575,13 @@ func (c *Controller) postgresqlCheck(obj interface{}) *acidv1.Postgresql {
 }
 
 /*
-  Ensures the pod service account and role bindings exists in a namespace
+Ensures the pod service account and role bindings exists in a namespace
-  before a PG cluster is created there so that a user does not have to deploy
+before a PG cluster is created there so that a user does not have to deploy
-  these credentials manually.  StatefulSets require the service account to
+these credentials manually.  StatefulSets require the service account to
-  create pods; Patroni requires relevant RBAC bindings to access endpoints
+create pods; Patroni requires relevant RBAC bindings to access endpoints
-  or config maps.
+or config maps.
 
-  The operator does not sync accounts/role bindings after creation.
+The operator does not sync accounts/role bindings after creation.
 */
 func (c *Controller) submitRBACCredentials(event ClusterEvent) error {
 

pkg/util/k8sutil/k8sutil.go

@@ -213,6 +213,37 @@ func (client *KubernetesClient) SetPostgresCRDStatus(clusterName spec.Namespaced
 	return pg, nil
 }
 
+// SetFinalizer of Postgres cluster
+func (client *KubernetesClient) SetFinalizer(clusterName spec.NamespacedName, pg *apiacidv1.Postgresql, finalizers []string) (*apiacidv1.Postgresql, error) {
+	var (
+		updatedPg *apiacidv1.Postgresql
+		patch     []byte
+		err       error
+	)
+	pg.ObjectMeta.SetFinalizers(finalizers)
+
+	if len(finalizers) > 0 {
+		patch, err = json.Marshal(struct {
+			PgMetadata interface{} `json:"metadata"`
+		}{&pg.ObjectMeta})
+		if err != nil {
+			return pg, fmt.Errorf("could not marshal ObjectMeta: %v", err)
+		}
+
+		updatedPg, err = client.PostgresqlsGetter.Postgresqls(clusterName.Namespace).Patch(
+			context.TODO(), clusterName.Name, types.MergePatchType, patch, metav1.PatchOptions{})
+	} else {
+		// in case finalizers are empty and update is needed to remove
+		updatedPg, err = client.PostgresqlsGetter.Postgresqls(clusterName.Namespace).Update(
+			context.TODO(), pg, metav1.UpdateOptions{})
+	}
+	if err != nil {
+		return updatedPg, fmt.Errorf("could not set finalizer: %v", err)
+	}
+
+	return updatedPg, nil
+}
+
 // SamePDB compares the PodDisruptionBudgets
 func SamePDB(cur, new *apipolicyv1.PodDisruptionBudget) (match bool, reason string) {
 	//TODO: improve comparison

pkg/util/util.go

@@ -152,6 +152,17 @@ func IsEqualIgnoreOrder(a, b []string) bool {
 	return reflect.DeepEqual(a_copy, b_copy)
 }
 
+// Iterate through slice and remove certain string, then return cleaned slice
+func RemoveString(slice []string, s string) (result []string) {
+	for _, item := range slice {
+		if item == s {
+			continue
+		}
+		result = append(result, item)
+	}
+	return result
+}
+
 // SliceReplaceElement
 func StringSliceReplaceElement(s []string, a, b string) (result []string) {
 	tmp := make([]string, 0, len(s))

pkg/util/util_test.go

@@ -66,6 +66,17 @@ var substractTest = []struct {
 	{[]string{"a"}, []string{""}, []string{"a"}, false},
 }
 
+var removeStringTest = []struct {
+	slice  []string
+	item   string
+	result []string
+}{
+	{[]string{"a", "b", "c"}, "b", []string{"a", "c"}},
+	{[]string{"a"}, "b", []string{"a"}},
+	{[]string{"a"}, "a", []string{}},
+	{[]string{}, "a", []string{}},
+}
+
 var sliceContaintsTest = []struct {
 	slice []string
 	item  string
@@ -200,6 +211,15 @@ func TestFindNamedStringSubmatch(t *testing.T) {
 	}
 }
 
+func TestRemoveString(t *testing.T) {
+	for _, tt := range removeStringTest {
+		res := RemoveString(tt.slice, tt.item)
+		if !IsEqualIgnoreOrder(res, tt.result) {
+			t.Errorf("RemoveString expected: %#v, got: %#v", tt.result, res)
+		}
+	}
+}
+
 func TestSliceContains(t *testing.T) {
 	for _, tt := range sliceContaintsTest {
 		res := SliceContains(tt.slice, tt.item)