add e2e test and pas switchover targets to recreatePods

e2e/scripts/watch_objects.sh

@@ -4,7 +4,7 @@ watch -c "
 kubectl get postgresql --all-namespaces
 echo
 echo -n 'Rolling upgrade pending: '
-kubectl get pods -o jsonpath='{.items..metadata.annotations.zalando-postgres-operator-rolling-update-required}'
+kubectl get pods -o jsonpath='{.items[].metadata.annotations.zalando-postgres-operator-rolling-update-required}'
 echo
 echo
 echo 'Pods'

e2e/tests/k8s_api.py

@@ -211,7 +211,7 @@ class K8s:
         self.wait_for_logical_backup_job(expected_num_of_jobs=1)
 
     def delete_operator_pod(self, step="Delete operator pod"):
-             # patching the pod template in the deployment restarts the operator pod
+        # patching the pod template in the deployment restarts the operator pod
         self.api.apps_v1.patch_namespaced_deployment("postgres-operator", "default", {"spec": {"template": {"metadata": {"annotations": {"step": "{}-{}".format(step, time.time())}}}}})
         self.wait_for_operator_pod_start()
 
@@ -219,8 +219,8 @@ class K8s:
         self.api.core_v1.patch_namespaced_config_map("postgres-operator", "default", config_map_patch)
         self.delete_operator_pod(step=step)
 
-    def patch_statefulset(self, data, name="acid-minimal-cluster", namespace="default"):
+    def patch_pod(self, data, pod_name, namespace="default"):
-        self.api.apps_v1.patch_namespaced_stateful_set(name, namespace, data)
+        self.api.core_v1.patch_namespaced_pod(pod_name, namespace, data)
 
     def create_with_kubectl(self, path):
         return subprocess.run(

e2e/tests/test_e2e.py

@@ -709,7 +709,6 @@ class EndToEndTestCase(unittest.TestCase):
         k8s.api.custom_objects_api.patch_namespaced_custom_object(
             "acid.zalan.do", "v1", "default", "postgresqls", "acid-minimal-cluster", pg_patch_resources)
 
-        k8s.patch_statefulset({"metadata": {"annotations": {"zalando-postgres-operator-rolling-update-required": "False"}}})
         k8s.update_config(patch_min_resource_limits, "Minimum resource test")
 
         self.eventuallyEqual(lambda: k8s.count_running_pods(), 2, "No two pods running after lazy rolling upgrade")
@@ -730,8 +729,6 @@ class EndToEndTestCase(unittest.TestCase):
 
     @classmethod
     def setUp(cls):
-        # cls.k8s.update_config({}, step="Setup")
-        cls.k8s.patch_statefulset({"meta": {"annotations": {"zalando-postgres-operator-rolling-update-required": False}}})
         pass
 
     @timeout_decorator.timeout(TEST_TIMEOUT_SEC)
@@ -762,6 +759,44 @@ class EndToEndTestCase(unittest.TestCase):
                 "acid.zalan.do", "v1", self.test_namespace, "postgresqls", "acid-test-cluster")
             time.sleep(5)
 
+    @timeout_decorator.timeout(TEST_TIMEOUT_SEC)
+    def test_rolling_update_flag(self):
+        '''
+            Add rolling update flag to only the master and see it failing over
+        '''
+        k8s = self.k8s
+        cluster_label = 'application=spilo,cluster-name=acid-minimal-cluster'
+
+        # verify we are in good state from potential previous tests
+        self.eventuallyEqual(lambda: k8s.count_running_pods(), 2, "No 2 pods running")
+
+         # rolling update annotation
+        flag = {
+            "metadata": {
+                "annotations": {
+                    "zalando-postgres-operator-rolling-update-required": "true",
+                }
+            }
+        }
+
+        podsList = k8s.api.core_v1.list_namespaced_pod('default', label_selector=cluster_label)
+        for pod in podsList.items:
+            # add flag only to the master to make it appear to the operator as a leftover from a rolling update
+            if pod.metadata.labels.get('spilo-role') == 'master':
+                k8s.patch_pod(flag, pod.metadata.name, pod.metadata.namespace)
+            # operator will perform a switchover to an existing replica before recreating the master pod
+            else:
+                switchover_target = pod.metadata.name
+
+        # do not wait until the next sync
+        k8s.delete_operator_pod()
+
+        # wait for the both pods to be up and running
+        self.eventuallyEqual(lambda: k8s.count_running_pods(), 2, "No 2 pods running")
+
+        # check if the former replica is now the new master
+        leader = k8s.get_cluster_leader_pod('acid-minimal-cluster')
+        self.eventuallyEqual(lambda: leader.metadata.name, switchover_target, "Rolling update flag did not trigger switchover")
 
     @timeout_decorator.timeout(TEST_TIMEOUT_SEC)
     def test_zz_node_readiness_label(self):

pkg/cluster/pod.go

@@ -373,15 +373,14 @@ func (c *Cluster) isSafeToRecreatePods(pods []v1.Pod) bool {
 	 XXX operator cannot forbid replica re-init, so we might still fail if re-init is started
 	 after this check succeeds but before a pod is re-created
 	*/
-	for i, pod := range pods {
+	for _, pod := range pods {
 		c.logger.Debugf("name=%s phase=%s ip=%s", pod.Name, pod.Status.Phase, pod.Status.PodIP)
 		var state string
 
 		err := retryutil.Retry(1*time.Second, 5*time.Second,
 			func() (bool, error) {
 				var err error
-				state, err = c.patroni.GetPatroniMemberState(&pods[i])
+				state, err = c.patroni.GetPatroniMemberState(&pod)
-
 				if err != nil {
 					return false, err
 				}
@@ -400,7 +399,7 @@ func (c *Cluster) isSafeToRecreatePods(pods []v1.Pod) bool {
 	return true
 }
 
-func (c *Cluster) recreatePods(pods []v1.Pod) error {
+func (c *Cluster) recreatePods(pods []v1.Pod, switchoverCandidates []spec.NamespacedName) error {
 	c.setProcessName("starting to recreate pods")
 	c.logger.Infof("there are %d pods in the cluster to recreate", len(pods))
 
@@ -411,7 +410,7 @@ func (c *Cluster) recreatePods(pods []v1.Pod) error {
 	var (
 		masterPod, newMasterPod *v1.Pod
 	)
-	replicas := make([]spec.NamespacedName, 0)
+	replicas := switchoverCandidates
 
 	for i, pod := range pods {
 		role := PostgresRole(pod.Labels[c.OpConfig.PodRoleLabel])

pkg/cluster/sync.go

@@ -277,7 +277,9 @@ func (c *Cluster) mustUpdatePodsAfterLazyUpdate(desiredSset *appsv1.StatefulSet)
 }
 
 func (c *Cluster) syncStatefulSet() error {
-	var podsToRecreate []v1.Pod
+
+	podsToRecreate := make([]v1.Pod, 0)
+	switchoverCandidates := make([]spec.NamespacedName, 0)
 
 	pods, err := c.listPods()
 	if err != nil {
@@ -318,6 +320,8 @@ func (c *Cluster) syncStatefulSet() error {
 		for _, pod := range pods {
 			if c.getRollingUpdateFlagFromPod(&pod) {
 				podsToRecreate = append(podsToRecreate, pod)
+			} else {
+				switchoverCandidates = append(switchoverCandidates, util.NameFromMeta(pod.ObjectMeta))
 			}
 		}
 
@@ -376,6 +380,8 @@ func (c *Cluster) syncStatefulSet() error {
 						c.logger.Warnf("updating rolling update flag failed for pod %q: %v", pod.Name, err)
 					}
 					podsToRecreate = append(podsToRecreate, pod)
+				} else {
+					switchoverCandidates = append(switchoverCandidates, util.NameFromMeta(pod.ObjectMeta))
 				}
 			}
 		}
@@ -393,7 +399,7 @@ func (c *Cluster) syncStatefulSet() error {
 	if len(podsToRecreate) > 0 {
 		c.logger.Debugln("performing rolling update")
 		c.eventRecorder.Event(c.GetReference(), v1.EventTypeNormal, "Update", "Performing rolling update")
-		if err := c.recreatePods(podsToRecreate); err != nil {
+		if err := c.recreatePods(podsToRecreate, switchoverCandidates); err != nil {
 			return fmt.Errorf("could not recreate pods: %v", err)
 		}
 		c.eventRecorder.Event(c.GetReference(), v1.EventTypeNormal, "Update", "Rolling update done - pods have been recreated")