Errors when received PVC shrink requests

controllers/reconcile_persistence.go

@@ -18,14 +18,14 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/client"
 )
 
-func (r *RabbitmqClusterReconciler) reconcilePVC(ctx context.Context, cluster *rabbitmqv1beta1.RabbitmqCluster, current, sts *appsv1.StatefulSet) error {
-	resize, err := r.needsPVCResize(current, sts)
+func (r *RabbitmqClusterReconciler) reconcilePVC(ctx context.Context, rmq *rabbitmqv1beta1.RabbitmqCluster, current, sts *appsv1.StatefulSet) error {
+	resize, err := r.needsPVCExpand(ctx, rmq, current, sts)
 	if err != nil {
 		return err
 	}
 
 	if resize {
-		if err := r.expandPVC(ctx, cluster, current, sts); err != nil {
+		if err := r.expandPVC(ctx, rmq, current, sts); err != nil {
 			return err
 		}
 	}
@@ -84,7 +84,11 @@ func (r *RabbitmqClusterReconciler) updatePVC(ctx context.Context, rmq *rabbitmq
 	return nil
 }
 
-func (r *RabbitmqClusterReconciler) needsPVCResize(current, desired *appsv1.StatefulSet) (bool, error) {
+// returns true if desired storage capacity is larger than the current storage; returns false when current and desired capacity is the same
+// errors when desired capacity is less than current capacity because PVC shrink is not supported by k8s
+func (r *RabbitmqClusterReconciler) needsPVCExpand(ctx context.Context, rmq *rabbitmqv1beta1.RabbitmqCluster, current, desired *appsv1.StatefulSet) (bool, error) {
+	logger := ctrl.LoggerFrom(ctx)
+
 	currentCapacity, err := persistenceStorageCapacity(current.Spec.VolumeClaimTemplates)
 	if err != nil {
 		return false, err
@@ -95,10 +99,20 @@ func (r *RabbitmqClusterReconciler) needsPVCResize(current, desired *appsv1.Stat
 		return false, err
 	}
 
-	if currentCapacity.Cmp(desiredCapacity) != 0 {
+	cmp := currentCapacity.Cmp(desiredCapacity)
+
+	// desired storage capacity is larger than the current capacity; PVC needs expansion
+	if cmp == -1 {
 		return true, nil
 	}
 
+	// desired storage capacity is less than the current capacity; logs and records a warning event
+	if cmp == 1 {
+		msg := "shrinking persistent volumes is not supported"
+		logger.Error(errors.New("unsupported operation"), msg)
+		r.Recorder.Event(rmq, corev1.EventTypeWarning, "FailedReconcilePersistence", msg)
+		return false, errors.New(msg)
+	}
 	return false, nil
 }
 

controllers/reconcile_persistence_test.go

@@ -0,0 +1,91 @@
+package controllers_test
+
+import (
+	"context"
+	"fmt"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+	rabbitmqv1beta1 "github.com/rabbitmq/cluster-operator/api/v1beta1"
+	"github.com/rabbitmq/cluster-operator/internal/status"
+	corev1 "k8s.io/api/core/v1"
+	apierrors "k8s.io/apimachinery/pkg/api/errors"
+	k8sresource "k8s.io/apimachinery/pkg/api/resource"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/types"
+	"k8s.io/utils/pointer"
+	runtimeClient "sigs.k8s.io/controller-runtime/pkg/client"
+)
+
+var _ = Describe("Persistence", func() {
+	var (
+		cluster          *rabbitmqv1beta1.RabbitmqCluster
+		defaultNamespace = "default"
+		ctx              = context.Background()
+	)
+
+	BeforeEach(func() {
+		cluster = &rabbitmqv1beta1.RabbitmqCluster{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      "rabbitmq-shrink",
+				Namespace: defaultNamespace,
+			},
+			Spec: rabbitmqv1beta1.RabbitmqClusterSpec{
+				Replicas: pointer.Int32Ptr(5),
+			},
+		}
+		Expect(client.Create(ctx, cluster)).To(Succeed())
+		waitForClusterCreation(ctx, cluster, client)
+	})
+
+	AfterEach(func() {
+		Expect(client.Delete(ctx, cluster)).To(Succeed())
+		Eventually(func() bool {
+			rmq := &rabbitmqv1beta1.RabbitmqCluster{}
+			err := client.Get(ctx, types.NamespacedName{Name: cluster.Name, Namespace: cluster.Namespace}, rmq)
+			return apierrors.IsNotFound(err)
+		}, 5).Should(BeTrue())
+	})
+
+	It("does not allow PVC shrink", func() {
+		By("not updating statefulSet volume claim storage capacity", func() {
+			tenG := k8sresource.MustParse("10Gi")
+			Expect(updateWithRetry(cluster, func(r *rabbitmqv1beta1.RabbitmqCluster) {
+				storage := k8sresource.MustParse("1Gi")
+				cluster.Spec.Persistence.Storage = &storage
+			})).To(Succeed())
+			Consistently(func() k8sresource.Quantity {
+				sts, err := clientSet.AppsV1().StatefulSets(defaultNamespace).Get(ctx, cluster.ChildResourceName("server"), metav1.GetOptions{})
+				Expect(err).NotTo(HaveOccurred())
+				return sts.Spec.VolumeClaimTemplates[0].Spec.Resources.Requests[corev1.ResourceStorage]
+			}, 10, 1).Should(Equal(tenG))
+		})
+
+		By("setting 'Warning' events", func() {
+			Expect(aggregateEventMsgs(ctx, cluster, "FailedReconcilePersistence")).To(
+				ContainSubstring("shrinking persistent volumes is not supported"))
+		})
+
+		By("setting ReconcileSuccess to 'false' with failed reason and message", func() {
+			Eventually(func() string {
+				rabbit := &rabbitmqv1beta1.RabbitmqCluster{}
+				Expect(client.Get(ctx, runtimeClient.ObjectKey{
+					Name:      cluster.Name,
+					Namespace: defaultNamespace,
+				}, rabbit)).To(Succeed())
+
+				for i := range rabbit.Status.Conditions {
+					if rabbit.Status.Conditions[i].Type == status.ReconcileSuccess {
+						return fmt.Sprintf(
+							"ReconcileSuccess status: %s, with reason: %s and message: %s",
+							rabbit.Status.Conditions[i].Status,
+							rabbit.Status.Conditions[i].Reason,
+							rabbit.Status.Conditions[i].Message)
+					}
+				}
+				return "ReconcileSuccess status: condition not present"
+			}, 5).Should(Equal("ReconcileSuccess status: False, " +
+				"with reason: FailedReconcilePVC " +
+				"and message: shrinking persistent volumes is not supported"))
+		})
+	})
+})