Recover expansion failure

pkg/api/persistentvolumeclaim/util.go

@@ -74,6 +74,21 @@ func EnforceDataSourceBackwardsCompatibility(pvcSpec, oldPVCSpec *core.Persisten
 	}
 }
 
+func DropDisabledFieldsFromStatus(pvc, oldPVC *core.PersistentVolumeClaim) {
+	if !utilfeature.DefaultFeatureGate.Enabled(features.ExpandPersistentVolumes) && oldPVC.Status.Conditions == nil {
+		pvc.Status.Conditions = nil
+	}
+
+	if !utilfeature.DefaultFeatureGate.Enabled(features.RecoverVolumeExpansionFailure) {
+		if !allocatedResourcesInUse(oldPVC) {
+			pvc.Status.AllocatedResources = nil
+		}
+		if !resizeStatusInUse(oldPVC) {
+			pvc.Status.ResizeStatus = nil
+		}
+	}
+}
+
 func dataSourceInUse(oldPVCSpec *core.PersistentVolumeClaimSpec) bool {
 	if oldPVCSpec == nil {
 		return false
@@ -118,3 +133,25 @@ func NormalizeDataSources(pvcSpec *core.PersistentVolumeClaimSpec) {
 		pvcSpec.DataSource = pvcSpec.DataSourceRef.DeepCopy()
 	}
 }
+
+func resizeStatusInUse(oldPVC *core.PersistentVolumeClaim) bool {
+	if oldPVC == nil {
+		return false
+	}
+	if oldPVC.Status.ResizeStatus != nil {
+		return true
+	}
+	return false
+}
+
+func allocatedResourcesInUse(oldPVC *core.PersistentVolumeClaim) bool {
+	if oldPVC == nil {
+		return false
+	}
+
+	if oldPVC.Status.AllocatedResources != nil {
+		return true
+	}
+
+	return false
+}

pkg/api/persistentvolumeclaim/util_test.go

@@ -22,6 +22,7 @@ import (
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
+	"k8s.io/apimachinery/pkg/api/resource"
 
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
 	featuregatetesting "k8s.io/component-base/featuregate/testing"
@@ -288,3 +289,111 @@ func TestDataSourceRef(t *testing.T) {
 		})
 	}
 }
+
+func TestDropDisabledFieldsFromStatus(t *testing.T) {
+	tests := []struct {
+		name     string
+		feature  bool
+		pvc      *core.PersistentVolumeClaim
+		oldPVC   *core.PersistentVolumeClaim
+		expected *core.PersistentVolumeClaim
+	}{
+		{
+			name:     "for:newPVC=hasAllocatedResource,oldPVC=doesnot,featuregate=false; should drop field",
+			feature:  false,
+			pvc:      withAllocatedResource("5G"),
+			oldPVC:   getPVC(),
+			expected: getPVC(),
+		},
+		{
+			name:     "for:newPVC=hasAllocatedResource,oldPVC=doesnot,featuregate=true; should keep field",
+			feature:  true,
+			pvc:      withAllocatedResource("5G"),
+			oldPVC:   getPVC(),
+			expected: withAllocatedResource("5G"),
+		},
+		{
+			name:     "for:newPVC=hasAllocatedResource,oldPVC=hasAllocatedResource,featuregate=true; should keep field",
+			feature:  true,
+			pvc:      withAllocatedResource("5G"),
+			oldPVC:   withAllocatedResource("5G"),
+			expected: withAllocatedResource("5G"),
+		},
+		{
+			name:     "for:newPVC=hasAllocatedResource,oldPVC=hasAllocatedResource,featuregate=false; should keep field",
+			feature:  false,
+			pvc:      withAllocatedResource("10G"),
+			oldPVC:   withAllocatedResource("5G"),
+			expected: withAllocatedResource("10G"),
+		},
+		{
+			name:     "for:newPVC=hasAllocatedResource,oldPVC=nil,featuregate=false; should drop field",
+			feature:  false,
+			pvc:      withAllocatedResource("5G"),
+			oldPVC:   nil,
+			expected: getPVC(),
+		},
+		{
+			name:     "for:newPVC=hasResizeStatus,oldPVC=nil, featuregate=false should drop field",
+			feature:  false,
+			pvc:      withResizeStatus(core.PersistentVolumeClaimNodeExpansionFailed),
+			oldPVC:   nil,
+			expected: getPVC(),
+		},
+		{
+			name:     "for:newPVC=hasResizeStatus,oldPVC=doesnot,featuregate=true; should keep field",
+			feature:  true,
+			pvc:      withResizeStatus(core.PersistentVolumeClaimNodeExpansionFailed),
+			oldPVC:   getPVC(),
+			expected: withResizeStatus(core.PersistentVolumeClaimNodeExpansionFailed),
+		},
+		{
+			name:     "for:newPVC=hasResizeStatus,oldPVC=hasResizeStatus,featuregate=true; should keep field",
+			feature:  true,
+			pvc:      withResizeStatus(core.PersistentVolumeClaimNodeExpansionFailed),
+			oldPVC:   withResizeStatus(core.PersistentVolumeClaimNodeExpansionFailed),
+			expected: withResizeStatus(core.PersistentVolumeClaimNodeExpansionFailed),
+		},
+		{
+			name:     "for:newPVC=hasResizeStatus,oldPVC=hasResizeStatus,featuregate=false; should keep field",
+			feature:  false,
+			pvc:      withResizeStatus(core.PersistentVolumeClaimNodeExpansionFailed),
+			oldPVC:   withResizeStatus(core.PersistentVolumeClaimNodeExpansionFailed),
+			expected: withResizeStatus(core.PersistentVolumeClaimNodeExpansionFailed),
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			defer featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.RecoverVolumeExpansionFailure, test.feature)()
+
+			DropDisabledFieldsFromStatus(test.pvc, test.oldPVC)
+
+			if !reflect.DeepEqual(*test.expected, *test.pvc) {
+				t.Errorf("Unexpected change: %+v", cmp.Diff(test.expected, test.pvc))
+			}
+		})
+	}
+}
+
+func getPVC() *core.PersistentVolumeClaim {
+	return &core.PersistentVolumeClaim{}
+}
+
+func withAllocatedResource(q string) *core.PersistentVolumeClaim {
+	return &core.PersistentVolumeClaim{
+		Status: core.PersistentVolumeClaimStatus{
+			AllocatedResources: core.ResourceList{
+				core.ResourceStorage: resource.MustParse(q),
+			},
+		},
+	}
+}
+
+func withResizeStatus(status core.PersistentVolumeClaimResizeStatus) *core.PersistentVolumeClaim {
+	return &core.PersistentVolumeClaim{
+		Status: core.PersistentVolumeClaimStatus{
+			ResizeStatus: &status,
+		},
+	}
+}

pkg/apis/core/types.go

@@ -430,6 +430,9 @@ type PersistentVolumeClaimSpec struct {
 	// +optional
 	Selector *metav1.LabelSelector
 	// Resources represents the minimum resources required
+	// If RecoverVolumeExpansionFailure feature is enabled users are allowed to specify resource requirements
+	// that are lower than previous value but must still be higher than capacity recorded in the
+	// status field of the claim.
 	// +optional
 	Resources ResourceRequirements
 	// VolumeName is the binding reference to the PersistentVolume backing this
@@ -486,6 +489,26 @@ const (
 	PersistentVolumeClaimFileSystemResizePending PersistentVolumeClaimConditionType = "FileSystemResizePending"
 )
 
+// +enum
+type PersistentVolumeClaimResizeStatus string
+
+const (
+	// When expansion is complete, the empty string is set by resize controller or kubelet.
+	PersistentVolumeClaimNoExpansionInProgress PersistentVolumeClaimResizeStatus = ""
+	// State set when resize controller starts expanding the volume in control-plane
+	PersistentVolumeClaimControllerExpansionInProgress PersistentVolumeClaimResizeStatus = "ControllerExpansionInProgress"
+	// State set when expansion has failed in resize controller with a terminal error.
+	// Transient errors such as timeout should not set this status and should leave ResizeStatus
+	// unmodified, so as resize controller can resume the volume expansion.
+	PersistentVolumeClaimControllerExpansionFailed PersistentVolumeClaimResizeStatus = "ControllerExpansionFailed"
+	// State set when resize controller has finished expanding the volume but further expansion is needed on the node.
+	PersistentVolumeClaimNodeExpansionPending PersistentVolumeClaimResizeStatus = "NodeExpansionPending"
+	// State set when kubelet starts expanding the volume.
+	PersistentVolumeClaimNodeExpansionInProgress PersistentVolumeClaimResizeStatus = "NodeExpansionInProgress"
+	// State set when expansion has failed in kubelet with a terminal error. Transient errors don't set NodeExpansionFailed.
+	PersistentVolumeClaimNodeExpansionFailed PersistentVolumeClaimResizeStatus = "NodeExpansionFailed"
+)
+
 // PersistentVolumeClaimCondition represents the current condition of PV claim
 type PersistentVolumeClaimCondition struct {
 	Type   PersistentVolumeClaimConditionType
@@ -513,6 +536,24 @@ type PersistentVolumeClaimStatus struct {
 	Capacity ResourceList
 	// +optional
 	Conditions []PersistentVolumeClaimCondition
+	// The storage resource within AllocatedResources tracks the capacity allocated to a PVC. It may
+	// be larger than the actual capacity when a volume expansion operation is requested.
+	// For storage quota, the larger value from allocatedResources and PVC.spec.resources is used.
+	// If allocatedResources is not set, PVC.spec.resources alone is used for quota calculation.
+	// If a volume expansion capacity request is lowered, allocatedResources is only
+	// lowered if there are no expansion operations in progress and if the actual volume capacity
+	// is equal or lower than the requested capacity.
+	// This is an alpha field and requires enabling RecoverVolumeExpansionFailure feature.
+	// +featureGate=RecoverVolumeExpansionFailure
+	// +optional
+	AllocatedResources ResourceList
+	// ResizeStatus stores status of resize operation.
+	// ResizeStatus is not set by default but when expansion is complete resizeStatus is set to empty
+	// string by resize controller or kubelet.
+	// This is an alpha field and requires enabling RecoverVolumeExpansionFailure feature.
+	// +featureGate=RecoverVolumeExpansionFailure
+	// +optional
+	ResizeStatus *PersistentVolumeClaimResizeStatus
 }
 
 // PersistentVolumeAccessMode defines various access modes for PV.