Add inplace pvc resize controller

This controller will directly resize the PVCs if it's enabled and if
the given cluster actually supports resizing PVCs on the fly.

Author: Kidswiss

.gitignore

@@ -1,5 +1,7 @@
 cover.out
 .github/release-notes.md
+.vscode
+__debug_bin*
 
 # Binaries for programs and plugins
 *.exe

controllers/inplace_controller.go

@@ -0,0 +1,79 @@
+package controllers
+
+import (
+	"context"
+	"time"
+
+	"github.com/vshn/statefulset-resize-controller/statefulset"
+	appsv1 "k8s.io/api/apps/v1"
+	apierrors "k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/client-go/tools/record"
+	ctrl "sigs.k8s.io/controller-runtime"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+	"sigs.k8s.io/controller-runtime/pkg/log"
+)
+
+// StatefulSetController is an interface for various implementations
+// of the StatefulSet controller.
+type StatefulSetController interface {
+	SetupWithManager(ctrl.Manager) error
+}
+
+// InplaceReconciler reconciles a StatefulSet object
+// It will resize the PVCs according to the sts template.
+type InplaceReconciler struct {
+	client.Client
+	Scheme   *runtime.Scheme
+	Recorder record.EventRecorder
+
+	RequeueAfter time.Duration
+	LabelName    string
+}
+
+// Reconcile is the main work loop, reacting to changes in statefulsets and initiating resizing of StatefulSets.
+func (r *InplaceReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
+	l := log.FromContext(ctx).WithValues("statefulset", req.NamespacedName)
+	ctx = log.IntoContext(ctx, l)
+
+	sts := &appsv1.StatefulSet{}
+	err := r.Client.Get(ctx, req.NamespacedName, sts)
+	if err != nil {
+		if apierrors.IsNotFound(err) {
+			return ctrl.Result{}, nil
+		}
+		return ctrl.Result{}, err
+	}
+
+	l.V(1).Info("Checking label for sts", "labelName", r.LabelName)
+	if sts.GetLabels()[r.LabelName] != "true" {
+		l.V(1).Info("Label not found, skipping sts")
+		return ctrl.Result{}, nil
+	}
+
+	l.Info("Found sts with label", "labelName", r.LabelName)
+
+	stsEntity, err := statefulset.NewEntity(sts)
+	if err != nil {
+		return ctrl.Result{}, err
+	}
+
+	stsEntity.Pvcs, err = fetchResizablePVCs(ctx, r.Client, *stsEntity)
+	if err != nil {
+		return ctrl.Result{}, err
+	}
+
+	if len(stsEntity.Pvcs) == 0 {
+		l.Info("All PVCs have the right size")
+		return ctrl.Result{}, nil
+	}
+
+	return ctrl.Result{}, resizePVCsInplace(ctx, r.Client, stsEntity.Pvcs)
+}
+
+// SetupWithManager sets up the controller with the Manager.
+func (r *InplaceReconciler) SetupWithManager(mgr ctrl.Manager) error {
+	return ctrl.NewControllerManagedBy(mgr).
+		For(&appsv1.StatefulSet{}).
+		Complete(r)
+}

controllers/pvc.go

@@ -16,14 +16,14 @@ import (
 )
 
 // getResizablePVCs fetches the information of all PVCs that are smaller than the request of the statefulset
-func (r StatefulSetReconciler) fetchResizablePVCs(ctx context.Context, si statefulset.Entity) ([]pvc.Entity, error) {
+func fetchResizablePVCs(ctx context.Context, cl client.Client, si statefulset.Entity) ([]pvc.Entity, error) {
 	// NOTE(glrf) This will get _all_ PVCs that belonged to the sts. Even the ones not used anymore (i.e. if scaled up and down).
 	sts, err := si.StatefulSet()
 	if err != nil {
 		return nil, err
 	}
 	pvcs := corev1.PersistentVolumeClaimList{}
-	if err := r.List(ctx, &pvcs, client.InNamespace(sts.Namespace), client.MatchingLabels(sts.Spec.Selector.MatchLabels)); err != nil {
+	if err := cl.List(ctx, &pvcs, client.InNamespace(sts.Namespace), client.MatchingLabels(sts.Spec.Selector.MatchLabels)); err != nil {
 		return nil, err
 	}
 	pis := filterResizablePVCs(ctx, *sts, pvcs.Items)
@@ -109,3 +109,22 @@ func (r *StatefulSetReconciler) resizePVCs(ctx context.Context, oldPIs []pvc.Ent
 	}
 	return pis, nil
 }
+
+func resizePVCsInplace(ctx context.Context, cl client.Client, PVCs []pvc.Entity) error {
+	l := log.FromContext(ctx)
+
+	for _, pvc := range PVCs {
+		l.Info("Updating PVC", "PVCName", pvc.SourceName)
+
+		resizedPVC := pvc.GetResizedSource()
+		resizedPVC.Spec.StorageClassName = pvc.SourceStorageClass
+		resizedPVC.Spec.VolumeName = pvc.Spec.VolumeName
+
+		err := cl.Update(ctx, resizedPVC)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}

controllers/statefulset.go

@@ -50,7 +50,7 @@ func (r StatefulSetReconciler) fetchStatefulSet(ctx context.Context, namespacedN
 	}
 
 	if !sts.Resizing() {
-		sts.Pvcs, err = r.fetchResizablePVCs(ctx, *sts)
+		sts.Pvcs, err = fetchResizablePVCs(ctx, r.Client, *sts)
 		return sts, err
 	}
 	return sts, nil

go.mod

@@ -4,6 +4,7 @@ go 1.16
 
 require (
 	github.com/stretchr/testify v1.7.0
+	go.uber.org/zap v1.18.1
 	k8s.io/api v0.21.3
 	k8s.io/apimachinery v0.21.3
 	k8s.io/client-go v0.21.3

main.go

@@ -7,6 +7,7 @@ import (
 
 	// Import all Kubernetes client auth plugins (e.g. Azure, GCP, OIDC, etc.)
 	// to ensure that exec-entrypoint and run can make use of them.
+	"go.uber.org/zap/zapcore"
 	_ "k8s.io/client-go/plugin/pkg/client/auth"
 
 	"k8s.io/apimachinery/pkg/runtime"
@@ -40,6 +41,9 @@ func main() {
 	var probeAddr string
 	var syncContainerImage string
 	var syncClusterRole string
+	var inplaceResize bool
+	var inplaceLabelName string
+	var logLevel int
 	flag.StringVar(&syncContainerImage, "sync-image", "instrumentisto/rsync-ssh", "A container image containing rsync, used to move data.")
 	flag.StringVar(&syncClusterRole, "sync-cluster-role", "", "ClusterRole to use for the sync jobs."+
 		"For example, this can be used to allow the sync job to run as root on a cluster with PSPs enabled by providing the name of a ClusterRole which allows usage of a privileged PSP.")
@@ -48,11 +52,16 @@ func main() {
 	flag.BoolVar(&enableLeaderElection, "leader-elect", false,
 		"Enable leader election for controller manager. "+
 			"Enabling this will ensure there is only one active controller manager.")
+	flag.BoolVar(&inplaceResize, "inplace", false, "Enable in-place update of PVCs. "+
+		"If the underlying storage supports direct resizing of the PVCs this should be used.")
+	flag.StringVar(&inplaceLabelName, "inplaceLabelName", "sts-resize.vshn.net/resize-inplace", "If inplace resize is enable the sts needs to have this label with value \"true\" in order to be handled.")
+	flag.IntVar(&logLevel, "log-level", 0, "Set the log level.")
+	flag.Parse()
+
 	opts := zap.Options{
 		Development: true,
+		Level:       zapcore.Level(logLevel * -1),
 	}
-	opts.BindFlags(flag.CommandLine)
-	flag.Parse()
 
 	ctrl.SetLogger(zap.New(zap.UseFlagOptions(&opts)))
 
@@ -69,14 +78,26 @@ func main() {
 		os.Exit(1)
 	}
 
-	if err = (&controllers.StatefulSetReconciler{
+	var stsController controllers.StatefulSetController = &controllers.StatefulSetReconciler{
 		Client:             mgr.GetClient(),
 		Scheme:             mgr.GetScheme(),
 		Recorder:           mgr.GetEventRecorderFor("statefulset-resize-controller"),
 		SyncContainerImage: syncContainerImage,
 		SyncClusterRole:    syncClusterRole,
 		RequeueAfter:       10 * time.Second,
-	}).SetupWithManager(mgr); err != nil {
+	}
+
+	if inplaceResize {
+		stsController = &controllers.InplaceReconciler{
+			Client:       mgr.GetClient(),
+			Scheme:       mgr.GetScheme(),
+			Recorder:     mgr.GetEventRecorderFor("statefulset-resize-controller"),
+			RequeueAfter: 10 * time.Second,
+			LabelName:    inplaceLabelName,
+		}
+	}
+
+	if err = stsController.SetupWithManager(mgr); err != nil {
 		setupLog.Error(err, "unable to create controller", "controller", "StatefulSet")
 		os.Exit(1)
 	}

pvc/pvc.go

@@ -15,13 +15,15 @@ const ManagedLabel = "sts-resize.vshn.net/managed"
 
 // NewEntity returns a new pvc Info
 func NewEntity(pvc corev1.PersistentVolumeClaim, growTo resource.Quantity, storageClassName *string) Entity {
+	sourceStorageClassName := pvc.Spec.StorageClassName
 	pvc.Spec.StorageClassName = storageClassName
 	return Entity{
 		SourceName:         pvc.Name,
 		Namespace:          pvc.Namespace,
 		Labels:             pvc.Labels,
 		TargetSize:         growTo,
 		TargetStorageClass: storageClassName,
+		SourceStorageClass: sourceStorageClassName,
 		Spec:               pvc.Spec,
 	}
 }
@@ -35,6 +37,7 @@ type Entity struct {
 	Spec               corev1.PersistentVolumeClaimSpec
 	TargetSize         resource.Quantity
 	TargetStorageClass *string
+	SourceStorageClass *string
 
 	BackedUp bool
 	Restored bool