steer rolling update via pod annotation

e2e/tests/test_e2e.py

@@ -588,7 +588,7 @@ class EndToEndTestCase(unittest.TestCase):
             k8s.update_config(unpatch_lazy_spilo_upgrade, step="patch lazy upgrade")
 
             # at this point operator will complete the normal rolling upgrade
-            # so we additonally test if disabling the lazy upgrade - forcing the normal rolling upgrade - works
+            # so we additionally test if disabling the lazy upgrade - forcing the normal rolling upgrade - works
             self.eventuallyEqual(lambda: k8s.get_effective_pod_image(pod0),
                                  conf_image, "Rolling upgrade was not executed",
                                  50, 3)

pkg/cluster/k8sres.go

@@ -6,7 +6,6 @@ import (
 	"fmt"
 	"path"
 	"sort"
-	"strconv"
 	"strings"
 
 	"github.com/sirupsen/logrus"
@@ -1279,8 +1278,6 @@ func (c *Cluster) generateStatefulSet(spec *acidv1.PostgresSpec) (*appsv1.Statef
 	}
 
 	stsAnnotations := make(map[string]string)
-	// TODO remove from sts
-	stsAnnotations[rollingUpdateStatefulsetAnnotationKey] = strconv.FormatBool(false)
 	stsAnnotations = c.AnnotationsToPropagate(c.annotationsSet(nil))
 
 	statefulSet := &appsv1.StatefulSet{

pkg/cluster/pod.go

@@ -4,11 +4,13 @@ import (
 	"context"
 	"fmt"
 	"math/rand"
+	"strconv"
 	"time"
 
 	appsv1 "k8s.io/api/apps/v1"
 	v1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/types"
 
 	"github.com/zalando/postgres-operator/pkg/spec"
 	"github.com/zalando/postgres-operator/pkg/util"
@@ -45,6 +47,93 @@ func (c *Cluster) getRolePods(role PostgresRole) ([]v1.Pod, error) {
 	return pods.Items, nil
 }
 
+// enableRollingUpdateFlagForPod sets the indicator for the rolling update requirement
+// in the Pod annotation.
+func (c *Cluster) enableRollingUpdateFlagForPod(pod v1.Pod, msg string) error {
+	c.logger.Debugf("enable rolling update annotation for %s: reason %s", pod.Name, msg)
+	flag := make(map[string]string)
+	flag[rollingUpdatePodAnnotationKey] = strconv.FormatBool(true)
+
+	patchData, err := metaAnnotationsPatch(flag)
+	if err != nil {
+		return fmt.Errorf("could not form patch for pod's rolling update flag: %v", err)
+	}
+
+	_, err = c.KubeClient.Pods(pod.Namespace).Patch(
+		context.TODO(),
+		pod.Name,
+		types.MergePatchType,
+		[]byte(patchData),
+		metav1.PatchOptions{},
+		"")
+	if err != nil {
+		return fmt.Errorf("could not patch pod rolling update flag %q: %v", patchData, err)
+	}
+
+	return nil
+}
+
+// enableRollingUpdateFlagForPods sets the indicator for the rolling update requirement
+// on pods that do not have it yet
+func (c *Cluster) enableRollingUpdateFlagForPods(pods []v1.Pod, msg string) error {
+	for _, pod := range pods {
+		if c.getRollingUpdateFlagFromPod(&pod, true) {
+			if err := c.enableRollingUpdateFlagForPod(pod, msg); err != nil {
+				return fmt.Errorf("enabling rolling update flag failed for pod %q: %v", pod.Name, err)
+			}
+		}
+	}
+
+	return nil
+}
+
+// getRollingUpdateFlagFromPod returns the value of the rollingUpdate flag from the passed
+// reverting to the default value in case of errors
+func (c *Cluster) getRollingUpdateFlagFromPod(pod *v1.Pod, defaultValue bool) (flag bool) {
+	anno := pod.GetAnnotations()
+	flag = defaultValue
+
+	stringFlag, exists := anno[rollingUpdatePodAnnotationKey]
+	if exists {
+		var err error
+		if flag, err = strconv.ParseBool(stringFlag); err != nil {
+			c.logger.Warnf("error when parsing %q annotation for the pod %q: expected boolean value, got %q\n",
+				rollingUpdatePodAnnotationKey,
+				types.NamespacedName{Namespace: pod.Namespace, Name: pod.Name},
+				stringFlag)
+			flag = defaultValue
+		}
+	}
+
+	return flag
+}
+
+// countPodsWithRollingUpdateFlag returns the value of the rollingUpdate flag from the passed pod
+// reverting to the default value in case of errors
+func (c *Cluster) countPodsWithRollingUpdateFlag(defaultValue bool) (int, int) {
+
+	pods, err := c.listPods()
+	if err != nil {
+		c.logger.Warnf("could not count pods with rolling update flag")
+		return 0, 0
+	}
+
+	desiredPodCount := c.Spec.NumberOfInstances
+	actualPodCount := len(pods)
+	podsToRollCount := int(desiredPodCount) - actualPodCount
+	if podsToRollCount < 0 {
+		podsToRollCount = 0
+	}
+
+	for _, pod := range pods {
+		if c.getRollingUpdateFlagFromPod(&pod, defaultValue) {
+			podsToRollCount++
+		}
+	}
+
+	return podsToRollCount, actualPodCount
+}
+
 func (c *Cluster) deletePods() error {
 	c.logger.Debugln("deleting pods")
 	pods, err := c.listPods()
@@ -364,6 +453,8 @@ func (c *Cluster) recreatePods() error {
 	)
 	replicas := make([]spec.NamespacedName, 0)
 	for i, pod := range pods.Items {
+		// only recreate pod if rolling update flag is true
+		if c.getRollingUpdateFlagFromPod(&pod, false) {
 			role := PostgresRole(pod.Labels[c.OpConfig.PodRoleLabel])
 
 			if role == Master {
@@ -381,10 +472,10 @@ func (c *Cluster) recreatePods() error {
 				newMasterPod = newPod
 			}
 		}
+	}
 
 	if masterPod != nil {
-		// failover if we have not observed a master pod when re-creating former replicas.
+		// failover if we have not observed a master pod when re-creating former replicas
-		// TODO if masterPod has no rolling update label anymore skip switchover too
 		if newMasterPod == nil && len(replicas) > 0 {
 			if err := c.Switchover(masterPod, masterCandidate(replicas)); err != nil {
 				c.logger.Warningf("could not perform switch over: %v", err)

pkg/cluster/resources.go

@@ -20,7 +20,7 @@ import (
 
 const (
 	// TODO rollingUpdatePodAnnotationKey = "zalando-postgres-operator-rolling-update-required"
-	rollingUpdateStatefulsetAnnotationKey = "zalando-postgres-operator-rolling-update-required"
+	rollingUpdatePodAnnotationKey = "zalando-postgres-operator-rolling-update-required"
 )
 
 func (c *Cluster) listResources() error {
@@ -148,84 +148,32 @@ func (c *Cluster) preScaleDown(newStatefulSet *appsv1.StatefulSet) error {
 	return nil
 }
 
-// TODO setRollingUpdateFlagForPod
-// setRollingUpdateFlagForStatefulSet sets the indicator or the rolling update requirement
-// in the StatefulSet annotation.
-func (c *Cluster) setRollingUpdateFlagForStatefulSet(sset *appsv1.StatefulSet, val bool, msg string) {
-	anno := sset.GetAnnotations()
-	if anno == nil {
-		anno = make(map[string]string)
-	}
-
-	anno[rollingUpdateStatefulsetAnnotationKey] = strconv.FormatBool(val)
-	sset.SetAnnotations(anno)
-	c.logger.Debugf("set statefulset's rolling update annotation to %t: caller/reason %s", val, msg)
-}
-
-// TODO applyRollingUpdateFlagForPod
-// applyRollingUpdateFlagforStatefulSet sets the rolling update flag for the cluster's StatefulSet
-// and applies that setting to the actual running cluster.
-func (c *Cluster) applyRollingUpdateFlagforStatefulSet(val bool) error {
-	c.setRollingUpdateFlagForStatefulSet(c.Statefulset, val, "applyRollingUpdateFlag")
-	sset, err := c.updateStatefulSetAnnotations(c.Statefulset.GetAnnotations())
-	if err != nil {
-		return err
-	}
-	c.Statefulset = sset
-	return nil
-}
-
-// TODO getRollingUpdateFlagFromPod
-// getRollingUpdateFlagFromStatefulSet returns the value of the rollingUpdate flag from the passed
-// StatefulSet, reverting to the default value in case of errors
-func (c *Cluster) getRollingUpdateFlagFromStatefulSet(sset *appsv1.StatefulSet, defaultValue bool) (flag bool) {
-	anno := sset.GetAnnotations()
-	flag = defaultValue
-
-	stringFlag, exists := anno[rollingUpdateStatefulsetAnnotationKey]
-	if exists {
-		var err error
-		if flag, err = strconv.ParseBool(stringFlag); err != nil {
-			c.logger.Warnf("error when parsing %q annotation for the statefulset %q: expected boolean value, got %q\n",
-				rollingUpdateStatefulsetAnnotationKey,
-				types.NamespacedName{Namespace: sset.Namespace, Name: sset.Name},
-				stringFlag)
-			flag = defaultValue
-		}
-	}
-	return flag
-}
-
-// TODO mergeRollingUpdateFlagUsingCache(runningPod *v1.Pod) bool {
 // mergeRollingUpdateFlagUsingCache returns the value of the rollingUpdate flag from the passed
 // statefulset, however, the value can be cleared if there is a cached flag in the cluster that
 // is set to false (the discrepancy could be a result of a failed StatefulSet update)
 func (c *Cluster) mergeRollingUpdateFlagUsingCache(runningStatefulSet *appsv1.StatefulSet) bool {
 	var (
-		cachedStatefulsetExists, clearRollingUpdateFromCache, podsRollingUpdateRequired bool
+		cachedStatefulsetExists, podsRollingUpdateRequired bool
 	)
 
 	if c.Statefulset != nil {
 		// if we reset the rolling update flag in the statefulset structure in memory but didn't manage to update
 		// the actual object in Kubernetes for some reason we want to avoid doing an unnecessary update by relying
 		// on the 'cached' in-memory flag.
+		c.logger.Debugf("cached StatefulSet value exists")
 		cachedStatefulsetExists = true
-		clearRollingUpdateFromCache = !c.getRollingUpdateFlagFromStatefulSet(c.Statefulset, true)
-		c.logger.Debugf("cached StatefulSet value exists, rollingUpdate flag is %t", clearRollingUpdateFromCache)
 	}
 
-	if podsRollingUpdateRequired = c.getRollingUpdateFlagFromStatefulSet(runningStatefulSet, false); podsRollingUpdateRequired {
+	podsToRollCount, podCount := c.countPodsWithRollingUpdateFlag(cachedStatefulsetExists)
-		if cachedStatefulsetExists && clearRollingUpdateFromCache {
+
-			c.logger.Infof("clearing the rolling update flag based on the cached information")
+	if podsToRollCount > 0 {
-			podsRollingUpdateRequired = false
+		c.logger.Debugf("%d / %d pods still need to be rotated", podsToRollCount, podCount)
-		} else {
+		podsRollingUpdateRequired = true
-			c.logger.Infof("found a statefulset with an unfinished rolling update of the pods")
-		}
 	}
+
 	return podsRollingUpdateRequired
 }
 
-// updatePodAnnotations
 func (c *Cluster) updateStatefulSetAnnotations(annotations map[string]string) (*appsv1.StatefulSet, error) {
 	c.logger.Debugf("patching statefulset annotations")
 	patchData, err := metaAnnotationsPatch(annotations)

pkg/cluster/sync.go

@@ -280,6 +280,12 @@ func (c *Cluster) syncStatefulSet() error {
 	var (
 		podsRollingUpdateRequired bool
 	)
+
+	pods, err := c.listPods()
+	if err != nil {
+		c.logger.Infof("could not list pods of the statefulset: %v", err)
+	}
+
 	// NB: Be careful to consider the codepath that acts on podsRollingUpdateRequired before returning early.
 	sset, err := c.KubeClient.StatefulSets(c.Namespace).Get(context.TODO(), c.statefulSetName(), metav1.GetOptions{})
 	if err != nil {
@@ -289,10 +295,6 @@ func (c *Cluster) syncStatefulSet() error {
 		// statefulset does not exist, try to re-create it
 		c.Statefulset = nil
 		c.logger.Infof("could not find the cluster's statefulset")
-		pods, err := c.listPods()
-		if err != nil {
-			return fmt.Errorf("could not list pods of the statefulset: %v", err)
-		}
 
 		sset, err = c.createStatefulSet()
 		if err != nil {
@@ -305,58 +307,73 @@ func (c *Cluster) syncStatefulSet() error {
 
 		podsRollingUpdateRequired = (len(pods) > 0)
 		if podsRollingUpdateRequired {
-			c.logger.Warningf("found pods from the previous statefulset: trigger rolling update")
+			if err = c.enableRollingUpdateFlagForPods(pods, "pods from previous statefulset"); err != nil {
-			if err := c.applyRollingUpdateFlagforStatefulSet(podsRollingUpdateRequired); err != nil {
+				c.logger.Warnf("updating rolling update flag for existing pods failed: %v", err)
-				return fmt.Errorf("could not set rolling update flag for the statefulset: %v", err)
 			}
 		}
 		c.logger.Infof("created missing statefulset %q", util.NameFromMeta(sset.ObjectMeta))
 
 	} else {
-		podsRollingUpdateRequired = c.mergeRollingUpdateFlagUsingCache(sset)
+		// check if there are still pods with a rolling update flag
+		// default value for flag depends on a potentially cached StatefulSet
+		podsToRollCount, podCount := c.countPodsWithRollingUpdateFlag(c.Statefulset != nil)
+
+		if podsToRollCount > 0 {
+			c.logger.Debugf("%d / %d pods still need to be rotated", podsToRollCount, podCount)
+			podsRollingUpdateRequired = true
+		}
+
 		// statefulset is already there, make sure we use its definition in order to compare with the spec.
 		c.Statefulset = sset
 
-		desiredSS, err := c.generateStatefulSet(&c.Spec)
+		desiredSts, err := c.generateStatefulSet(&c.Spec)
 		if err != nil {
 			return fmt.Errorf("could not generate statefulset: %v", err)
 		}
-		c.setRollingUpdateFlagForStatefulSet(desiredSS, podsRollingUpdateRequired, "from cache")
 
-		cmp := c.compareStatefulSetWith(desiredSS)
+		cmp := c.compareStatefulSetWith(desiredSts)
 		if !cmp.match {
 			if cmp.rollingUpdate && !podsRollingUpdateRequired {
-				podsRollingUpdateRequired = true
+				podsRollingUpdateRequired = cmp.rollingUpdate
-				c.setRollingUpdateFlagForStatefulSet(desiredSS, podsRollingUpdateRequired, "statefulset changes")
+				if err = c.enableRollingUpdateFlagForPods(pods, "pod changes"); err != nil {
+					return fmt.Errorf("updating rolling update flag for pods failed: %v", err)
+				}
 			}
 
-			c.logStatefulSetChanges(c.Statefulset, desiredSS, false, cmp.reasons)
+			c.logStatefulSetChanges(c.Statefulset, desiredSts, false, cmp.reasons)
 
 			if !cmp.replace {
-				if err := c.updateStatefulSet(desiredSS); err != nil {
+				if err := c.updateStatefulSet(desiredSts); err != nil {
 					return fmt.Errorf("could not update statefulset: %v", err)
 				}
 			} else {
-				if err := c.replaceStatefulSet(desiredSS); err != nil {
+				if err := c.replaceStatefulSet(desiredSts); err != nil {
 					return fmt.Errorf("could not replace statefulset: %v", err)
 				}
 			}
 		}
 
+		// TODO why is this necessary?
 		c.updateStatefulSetAnnotations(c.AnnotationsToPropagate(c.annotationsSet(c.Statefulset.Annotations)))
 
 		if !podsRollingUpdateRequired && !c.OpConfig.EnableLazySpiloUpgrade {
-			// even if desired and actual statefulsets match
+			// even if the desired and the running statefulsets match
 			// there still may be not up-to-date pods on condition
 			//  (a) the lazy update was just disabled
 			// and
 			//  (b) some of the pods were not restarted when the lazy update was still in place
-			podsRollingUpdateRequired, err = c.mustUpdatePodsAfterLazyUpdate(desiredSS)
+			for _, pod := range pods {
-			if err != nil {
+				effectivePodImage := pod.Spec.Containers[0].Image
-				return fmt.Errorf("could not list pods of the statefulset: %v", err)
+				stsImage := desiredSts.Spec.Template.Spec.Containers[0].Image
-			}
-		}
 
+				if stsImage != effectivePodImage {
+					podsRollingUpdateRequired = true
+					if err = c.enableRollingUpdateFlagForPod(pod, "pod not yet restarted due to lazy update"); err != nil {
+						c.logger.Warnf("updating rolling update flag failed for pod %q: %v", pod.Name, err)
+					}
+				}
+			}
+		}
 	}
 
 	// Apply special PostgreSQL parameters that can only be set via the Patroni API.
@@ -376,9 +393,6 @@ func (c *Cluster) syncStatefulSet() error {
 		}
 		c.logger.Infof("pods have been recreated")
 		c.eventRecorder.Event(c.GetReference(), v1.EventTypeNormal, "Update", "Rolling update done - pods have been recreated")
-		if err := c.applyRollingUpdateFlagforStatefulSet(false); err != nil {
-			c.logger.Warningf("could not clear rolling update for the statefulset: %v", err)
-		}
 	}
 	return nil
 }