Check if PV/PVC Access Modes are Supported by the Volume Provider

README.md

@@ -3,12 +3,26 @@
 pvmigrate allows migrating PVCs between two StorageClasses by creating new PVs, copying over the data, and then changing
 PVCs to refer to the new PVs.
 
+## Preflight Validation
+
+`pvmigrate` will run preflight migration validation to catch any potential failures prior to the migration. 
+
+Currently supported validations are: 
+- Checking for existence of storage classes
+- Checking existing PVC access modes are supported on the destination storage provider
+
 ## Examples
 
 To migrate PVs from the 'default' StorageClass to mynewsc:
 
 ```bash
-pvmigrate --source-sc default --dest-sc mynewsc
+pvmigrate --source-sc "default" --dest-sc "mynewsc"
+```
+
+To run preflight migration validation without actually running the migration operation:
+
+```bash
+pvmigrate --source-sc "source" --dest-sc "destination" --preflight-validation-only
 ```
 
 ## Flags
@@ -22,6 +36,9 @@ pvmigrate --source-sc default --dest-sc mynewsc
 | --set-defaults           | Bool   |          | false            | change default storage class from source to dest                                                 |
 | --verbose-copy           | Bool   |          | false            | show output from the rsync command used to copy data between PVCs                                |
 | --skip-source-validation | Bool   |          | false            | migrate from PVCs using a particular StorageClass name, even if that StorageClass does not exist |
+| --preflight-validation-only | Bool | | false | skip the migration and run preflight validation only |
+| --skip-preflight-validation | Bool | | false | skip preflight migration validation on the destination storage provider |
+| --pod-ready-timeout | time.Duration | | 60 seconds | length of time to wait (in seconds) for validation pod(s) to go into Ready phase |
 
 ## Process
 

cmd/main.go

@@ -7,6 +7,7 @@ import (
 	"log"
 	"os"
 	"os/signal"
+	"time"
 
 	"github.com/replicatedhq/pvmigrate/pkg/migrate"
 	"github.com/replicatedhq/pvmigrate/pkg/preflight"
@@ -34,8 +35,8 @@ func main() {
 	flag.BoolVar(&options.SetDefaults, "set-defaults", false, "change default storage class from source to dest")
 	flag.BoolVar(&options.VerboseCopy, "verbose-copy", false, "show output from the rsync command used to copy data between PVCs")
 	flag.BoolVar(&options.SkipSourceValidation, "skip-source-validation", false, "migrate from PVCs using a particular StorageClass name, even if that StorageClass does not exist")
-	flag.IntVar(&options.PodReadyTimeout, "pod-ready-timeout", 60, "length of time to wait (in seconds) for volume validation pod(s) to go into Ready phase")
-	flag.BoolVar(&skipPreflightValidation, "skip-preflight-validation", false, "skip the volume access modes validation on the destination storage provider")
+	flag.DurationVar(&options.PodReadyTimeout, "pod-ready-timeout", 60*time.Second, "length of time to wait (in seconds) for validation pod(s) to go into Ready phase")
+	flag.BoolVar(&skipPreflightValidation, "skip-preflight-validation", false, "skip preflight migration validation on the destination storage provider")
 	flag.BoolVar(&preflightValidationOnly, "preflight-validation-only", false, "skip the migration and run preflight validation only")
 
 	flag.Parse()

pkg/migrate/migrate.go

@@ -24,7 +24,7 @@ const (
 	scaleAnnotation          = baseAnnotation + "-scale"
 	kindAnnotation           = baseAnnotation + "-kind"
 	sourceNsAnnotation       = baseAnnotation + "-sourcens"
-	sourcePvcAnnotation      = baseAnnotation + "-sourcepvc"
+	sourcePVCAnnotation      = baseAnnotation + "-sourcepvc"
 	desiredReclaimAnnotation = baseAnnotation + "-reclaim"
 )
 
@@ -47,7 +47,7 @@ type Options struct {
 	SetDefaults          bool
 	VerboseCopy          bool
 	SkipSourceValidation bool
-	PodReadyTimeout      int
+	PodReadyTimeout      time.Duration
 }
 
 // Migrate moves data and PVCs from one StorageClass to another
@@ -537,7 +537,6 @@ func getPVCs(ctx context.Context, w *log.Logger, clientset k8sclient.Interface,
 	return matchingPVCs, pvcNamespaces, nil
 }
 
-// TODO: move this to the validation package
 func validateStorageClasses(ctx context.Context, w *log.Logger, clientset k8sclient.Interface, sourceSCName string, destSCName string, skipSourceValidation bool) error {
 	// get storage providers
 	storageClasses, err := clientset.StorageV1().StorageClasses().List(ctx, metav1.ListOptions{})
@@ -579,6 +578,7 @@ const nameSuffix = "-pvcmigrate"
 // pruning from the end runs the risk of dropping the '0'/'1'/etc of a statefulset's PVC name
 // pruning from the front runs the risk of making a-replica-... and b-replica-... collide
 // so this removes characters from the middle of the string
+// TODO: refactor to k8sutil package
 func newPvcName(originalName string) string {
 	candidate := originalName + nameSuffix
 	if len(candidate) <= 63 {
@@ -957,7 +957,7 @@ func swapPVs(ctx context.Context, w *log.Logger, clientset k8sclient.Interface,
 	err = mutatePV(ctx, w, clientset, migratedPVC.Spec.VolumeName, func(volume *corev1.PersistentVolume) *corev1.PersistentVolume {
 		// add annotations describing what PVC this data came from in case of a failure later
 		volume.Annotations[sourceNsAnnotation] = ns
-		volume.Annotations[sourcePvcAnnotation] = pvcName
+		volume.Annotations[sourcePVCAnnotation] = pvcName
 
 		// this will be used to set the reclaim policy after attaching a new PVC
 		volume.Annotations[desiredReclaimAnnotation] = string(originalReclaim)

pkg/migrate/migrate_test.go

@@ -1389,7 +1389,7 @@ func Test_swapPVs(t *testing.T) {
 						Annotations: map[string]string{
 							desiredReclaimAnnotation: "Delete",
 							sourceNsAnnotation:       "testns",
-							sourcePvcAnnotation:      "sourcepvc",
+							sourcePVCAnnotation:      "sourcepvc",
 							"testannotation":         "dest-pv",
 						},
 					},

pkg/preflight/validate.go

@@ -41,12 +41,23 @@ type ValidationFailure struct {
 
 // Validate runs preflight check on storage volumes returning a list of failures
 func Validate(ctx context.Context, w *log.Logger, clientset k8sclient.Interface, options migrate.Options) ([]ValidationFailure, error) {
+	// validate storage classes
+	scFailures, err := validateStorageClasses(ctx, w, clientset, options.SourceSCName, options.DestSCName)
+	if err != nil {
+		return nil, fmt.Errorf("failed to validate storage classes: %w", err)
+	}
+
+	// if there are storage class validation failures it doesn't make sense to proceed
+	if scFailures != nil {
+		return scFailures, nil
+	}
+
 	// validate access modes for all PVCs using the source storage class
 	pvcs, err := pvcsForStorageClass(ctx, w, clientset, options.SourceSCName, options.Namespace)
 	if err != nil {
 		return nil, fmt.Errorf("failed to get PVCs for storage %s: %w", options.SourceSCName, err)
 	}
-	pvcAccesModeFailures, err := validateVolumeAccessModes(ctx, w, clientset, options.DestSCName, options.RsyncImage, time.Duration(options.PodReadyTimeout)*time.Second, pvcs)
+	pvcAccesModeFailures, err := validateVolumeAccessModes(ctx, w, clientset, options.DestSCName, options.RsyncImage, options.PodReadyTimeout, pvcs)
 	if err != nil {
 		return nil, fmt.Errorf("failed to validate PVC access modes: %w", err)
 	}
@@ -56,7 +67,7 @@ func Validate(ctx context.Context, w *log.Logger, clientset k8sclient.Interface,
 // PrintPVAccessModeErrors prints and formats the volume access mode errors in pvcErrors
 func PrintValidationFailures(stream io.Writer, failures []ValidationFailure) {
 	tw := tabwriter.NewWriter(stream, 0, 8, 8, '\t', 0)
-	fmt.Fprintf(tw, "The following resources cannot be migrated:\n\n")
+	fmt.Fprintf(tw, "The following resources failed validation:\n")
 	fmt.Fprintln(tw, "NAMESPACE\tRESOURCE\tMESSAGE")
 	fmt.Fprintf(tw, "---------\t--------\t-------\n")
 	for _, failure := range failures {
@@ -98,6 +109,34 @@ func validateVolumeAccessModes(ctx context.Context, l *log.Logger, client k8scli
 	return volAccessModeFailures, nil
 }
 
+// validateStorageClasses returns any failures encountered when discovering the source and destination
+// storage classes
+func validateStorageClasses(ctx context.Context, l *log.Logger, clientset k8sclient.Interface, sourceSCName, destSCName string) ([]ValidationFailure, error) {
+	// get storage providers
+	storageClasses, err := clientset.StorageV1().StorageClasses().List(ctx, metav1.ListOptions{})
+	if err != nil {
+		return nil, fmt.Errorf("failed to list storage classes: %w", err)
+	}
+
+	var sourceScFound, destScFound bool
+	var scFailures []ValidationFailure
+	for _, sc := range storageClasses.Items {
+		if sc.Name == sourceSCName {
+			sourceScFound = true
+		}
+		if sc.Name == destSCName {
+			destScFound = true
+		}
+	}
+	if !sourceScFound {
+		scFailures = append(scFailures, ValidationFailure{Resource: "sc/" + sourceSCName, Message: "Resource not found"})
+	}
+	if !destScFound {
+		scFailures = append(scFailures, ValidationFailure{Resource: "sc/" + destSCName, Message: "Resource not found"})
+	}
+	return scFailures, nil
+}
+
 // buildTmpPVCConsumerPod creates a pod spec for consuming a pvc
 func buildTmpPVCConsumerPod(pvcName, namespace, image string) *corev1.Pod {
 	return &corev1.Pod{

pkg/preflight/validate_test.go

@@ -868,3 +868,81 @@ func Test_pvcsForStorageClass(t *testing.T) {
 		})
 	}
 }
+
+func Test_validateStorageClasses(t *testing.T) {
+	for _, tt := range []struct {
+		name      string
+		resources []runtime.Object
+		sourceSC  string
+		destSC    string
+		wantErr   bool
+		expected  []ValidationFailure
+	}{
+		{
+			name:     "When both StorageClasses exist and are distinct expect no failures",
+			sourceSC: "sourcesc",
+			destSC:   "destsc",
+			resources: []runtime.Object{
+				&storagev1.StorageClass{
+					ObjectMeta: metav1.ObjectMeta{
+						Name: "sourcesc",
+					},
+				},
+				&storagev1.StorageClass{
+					ObjectMeta: metav1.ObjectMeta{
+						Name: "destsc",
+					},
+				},
+			},
+		},
+		{
+			name:     "When source storage class does not exist expect validation failure",
+			sourceSC: "sourcesc",
+			destSC:   "destsc",
+			resources: []runtime.Object{
+				&storagev1.StorageClass{
+					ObjectMeta: metav1.ObjectMeta{
+						Name: "destsc",
+					},
+				},
+			},
+			expected: []ValidationFailure{
+				{
+					Resource: "sc/sourcesc",
+					Message:  "Resource not found",
+				},
+			},
+		},
+		{
+			name:     "When destination storage class does not exist expect validation failure",
+			sourceSC: "sourcesc",
+			destSC:   "destsc",
+			resources: []runtime.Object{
+				&storagev1.StorageClass{
+					ObjectMeta: metav1.ObjectMeta{
+						Name: "sourcesc",
+					},
+				},
+			},
+			expected: []ValidationFailure{
+				{
+					Resource: "sc/destsc",
+					Message:  "Resource not found",
+				},
+			},
+		},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			req := require.New(t)
+			clientset := fake.NewSimpleClientset(tt.resources...)
+			logger := log.New(io.Discard, "", 0)
+			result, err := validateStorageClasses(context.Background(), logger, clientset, tt.sourceSC, tt.destSC)
+			if !tt.wantErr {
+				req.NoError(err)
+			} else {
+				req.Error(err)
+			}
+			req.Equal(result, tt.expected)
+		})
+	}
+}