Implement PVC or EmptyDir for Storage (#67)

fixes #49

Author: sircthulhu

api/v1alpha1/etcdcluster_types.go

@@ -17,23 +17,18 @@ limitations under the License.
 package v1alpha1
 
 import (
-	"k8s.io/apimachinery/pkg/api/resource"
+	corev1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
 
-type Storage struct {
-	StorageClass string            `json:"storageClass"`
-	Size         resource.Quantity `json:"size"`
-}
-
 // EtcdClusterSpec defines the desired state of EtcdCluster
 type EtcdClusterSpec struct {
 	// Replicas is the count of etcd instances in cluster.
 	// +optional
 	// +kubebuilder:default:=3
 	// +kubebuilder:validation:Minimum:=0
-	Replicas *int32  `json:"replicas,omitempty"`
-	Storage  Storage `json:"storage,omitempty"`
+	Replicas *int32      `json:"replicas,omitempty"`
+	Storage  StorageSpec `json:"storage"`
 }
 
 const (
@@ -76,6 +71,67 @@ type EtcdClusterList struct {
 	Items           []EtcdCluster `json:"items"`
 }
 
+// EmbeddedObjectMetadata contains a subset of the fields included in k8s.io/apimachinery/pkg/apis/meta/v1.ObjectMeta
+// Only fields which are relevant to embedded resources are included.
+type EmbeddedObjectMetadata struct {
+	// Name must be unique within a namespace. Is required when creating resources, although
+	// some resources may allow a client to request the generation of an appropriate name
+	// automatically. Name is primarily intended for creation idempotence and configuration
+	// definition.
+	// Cannot be updated.
+	// More info: https://kubernetes.io/docs/concepts/overview/working-with-objects/names#names
+	// +optional
+	Name string `json:"name,omitempty" protobuf:"bytes,1,opt,name=name"`
+
+	// Labels Map of string keys and values that can be used to organize and categorize
+	// (scope and select) objects. May match selectors of replication controllers
+	// and services.
+	// More info: https://kubernetes.io/docs/concepts/overview/working-with-objects/labels
+	// +optional
+	Labels map[string]string `json:"labels,omitempty" protobuf:"bytes,11,rep,name=labels"`
+
+	// Annotations is an unstructured key value map stored with a resource that may be
+	// set by external tools to store and retrieve arbitrary metadata. They are not
+	// queryable and should be preserved when modifying objects.
+	// More info: https://kubernetes.io/docs/concepts/overview/working-with-objects/annotations
+	// +optional
+	Annotations map[string]string `json:"annotations,omitempty" protobuf:"bytes,12,rep,name=annotations"`
+}
+
+// StorageSpec defines the configured storage for a etcd members.
+// If neither `emptyDir` nor `volumeClaimTemplate` is specified, then by default an [EmptyDir](https://kubernetes.io/docs/concepts/storage/volumes/#emptydir) will be used.
+// +k8s:openapi-gen=true
+type StorageSpec struct {
+	// EmptyDirVolumeSource to be used by the StatefulSets. If specified, used in place of any volumeClaimTemplate. More
+	// info: https://kubernetes.io/docs/concepts/storage/volumes/#emptydir
+	// +optional
+	EmptyDir *corev1.EmptyDirVolumeSource `json:"emptyDir,omitempty"`
+	// A PVC spec to be used by the StatefulSets.
+	// +optional
+	VolumeClaimTemplate EmbeddedPersistentVolumeClaim `json:"volumeClaimTemplate,omitempty"`
+}
+
+// EmbeddedPersistentVolumeClaim is an embedded version of k8s.io/api/core/v1.PersistentVolumeClaim.
+// It contains TypeMeta and a reduced ObjectMeta.
+type EmbeddedPersistentVolumeClaim struct {
+	metav1.TypeMeta `json:",inline"`
+
+	// EmbeddedMetadata contains metadata relevant to an EmbeddedResource.
+	// +optional
+	EmbeddedObjectMetadata `json:"metadata,omitempty" protobuf:"bytes,1,opt,name=metadata"`
+
+	// Spec defines the desired characteristics of a volume requested by a pod author.
+	// More info: https://kubernetes.io/docs/concepts/storage/persistent-volumes#persistentvolumeclaims
+	// +optional
+	Spec corev1.PersistentVolumeClaimSpec `json:"spec,omitempty" protobuf:"bytes,2,opt,name=spec"`
+
+	// Status represents the current information/status of a persistent volume claim.
+	// Read-only.
+	// More info: https://kubernetes.io/docs/concepts/storage/persistent-volumes#persistentvolumeclaims
+	// +optional
+	Status corev1.PersistentVolumeClaimStatus `json:"status,omitempty" protobuf:"bytes,3,opt,name=status"`
+}
+
 func init() {
 	SchemeBuilder.Register(&EtcdCluster{}, &EtcdClusterList{})
 }

api/v1alpha1/etcdcluster_webhook.go

@@ -17,8 +17,12 @@ limitations under the License.
 package v1alpha1
 
 import (
+	corev1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/api/errors"
 	"k8s.io/apimachinery/pkg/api/resource"
 	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/apimachinery/pkg/util/validation/field"
 	ctrl "sigs.k8s.io/controller-runtime"
 	logf "sigs.k8s.io/controller-runtime/pkg/log"
 	"sigs.k8s.io/controller-runtime/pkg/webhook"
@@ -42,8 +46,16 @@ var _ webhook.Defaulter = &EtcdCluster{}
 // Default implements webhook.Defaulter so a webhook will be registered for the type
 func (r *EtcdCluster) Default() {
 	etcdclusterlog.Info("default", "name", r.Name)
-	if r.Spec.Storage.Size.IsZero() {
-		r.Spec.Storage.Size = resource.MustParse("4Gi")
+	if r.Spec.Storage.EmptyDir == nil {
+		if len(r.Spec.Storage.VolumeClaimTemplate.Spec.AccessModes) == 0 {
+			r.Spec.Storage.VolumeClaimTemplate.Spec.AccessModes = []corev1.PersistentVolumeAccessMode{corev1.ReadWriteOnce}
+		}
+		storage := r.Spec.Storage.VolumeClaimTemplate.Spec.Resources.Requests.Storage()
+		if storage == nil || storage.IsZero() {
+			r.Spec.Storage.VolumeClaimTemplate.Spec.Resources.Requests = corev1.ResourceList{
+				corev1.ResourceStorage: resource.MustParse("4Gi"),
+			}
+		}
 	}
 }
 
@@ -61,9 +73,27 @@ func (r *EtcdCluster) ValidateCreate() (admission.Warnings, error) {
 func (r *EtcdCluster) ValidateUpdate(old runtime.Object) (admission.Warnings, error) {
 	etcdclusterlog.Info("validate update", "name", r.Name)
 	var warnings admission.Warnings
-	if old.(*EtcdCluster).Spec.Replicas != r.Spec.Replicas {
+	oldCluster := old.(*EtcdCluster)
+	if *oldCluster.Spec.Replicas != *r.Spec.Replicas {
 		warnings = append(warnings, "cluster resize is not currently supported")
 	}
+
+	var allErrors field.ErrorList
+	if oldCluster.Spec.Storage.EmptyDir != r.Spec.Storage.EmptyDir {
+		allErrors = append(allErrors, field.Invalid(
+			field.NewPath("spec", "storage", "emptyDir"),
+			r.Spec.Storage.EmptyDir,
+			"field is immutable"),
+		)
+	}
+
+	if len(allErrors) > 0 {
+		err := errors.NewInvalid(
+			schema.GroupKind{Group: GroupVersion.Group, Kind: "EtcdCluster"},
+			r.Name, allErrors)
+		return warnings, err
+	}
+
 	return warnings, nil
 }
 

api/v1alpha1/etcdcluster_webhook_test.go

@@ -19,6 +19,8 @@ package v1alpha1
 import (
 	. "github.com/onsi/ginkgo/v2"
 	"github.com/onsi/gomega"
+	corev1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/api/errors"
 	"k8s.io/apimachinery/pkg/api/resource"
 	"k8s.io/utils/ptr"
 )
@@ -30,22 +32,39 @@ var _ = Describe("EtcdCluster Webhook", func() {
 			etcdCluster := &EtcdCluster{}
 			etcdCluster.Default()
 			gomega.Expect(etcdCluster.Spec.Replicas).To(gomega.BeNil(), "User should have an opportunity to create cluster with 0 replicas")
-			gomega.Expect(etcdCluster.Spec.Storage.Size).To(gomega.Equal(resource.MustParse("4Gi")))
+			gomega.Expect(etcdCluster.Spec.Storage.EmptyDir).To(gomega.BeNil())
+			storage := etcdCluster.Spec.Storage.VolumeClaimTemplate.Spec.Resources.Requests.Storage()
+			if gomega.Expect(storage).NotTo(gomega.BeNil()) {
+				gomega.Expect(*storage).To(gomega.Equal(resource.MustParse("4Gi")))
+			}
 		})
 
 		It("Should not override fields with default values if not empty", func() {
 			etcdCluster := &EtcdCluster{
 				Spec: EtcdClusterSpec{
 					Replicas: ptr.To(int32(5)),
-					Storage: Storage{
-						StorageClass: "local-path",
-						Size:         resource.MustParse("10Gi"),
+					Storage: StorageSpec{
+						VolumeClaimTemplate: EmbeddedPersistentVolumeClaim{
+							Spec: corev1.PersistentVolumeClaimSpec{
+								AccessModes:      []corev1.PersistentVolumeAccessMode{corev1.ReadWriteOnce},
+								StorageClassName: ptr.To("local-path"),
+								Resources: corev1.VolumeResourceRequirements{
+									Requests: map[corev1.ResourceName]resource.Quantity{
+										corev1.ResourceStorage: resource.MustParse("10Gi"),
+									},
+								},
+							},
+						},
 					},
 				},
 			}
 			etcdCluster.Default()
 			gomega.Expect(*etcdCluster.Spec.Replicas).To(gomega.Equal(int32(5)))
-			gomega.Expect(etcdCluster.Spec.Storage.Size).To(gomega.Equal(resource.MustParse("10Gi")))
+			gomega.Expect(etcdCluster.Spec.Storage.EmptyDir).To(gomega.BeNil())
+			storage := etcdCluster.Spec.Storage.VolumeClaimTemplate.Spec.Resources.Requests.Storage()
+			if gomega.Expect(storage).NotTo(gomega.BeNil()) {
+				gomega.Expect(*storage).To(gomega.Equal(resource.MustParse("10Gi")))
+			}
 		})
 	})
 
@@ -62,4 +81,26 @@ var _ = Describe("EtcdCluster Webhook", func() {
 		})
 	})
 
+	Context("When updating EtcdCluster under Validating Webhook", func() {
+		It("Should reject changing storage type", func() {
+			etcdCluster := &EtcdCluster{
+				Spec: EtcdClusterSpec{
+					Replicas: ptr.To(int32(1)),
+					Storage:  StorageSpec{EmptyDir: &corev1.EmptyDirVolumeSource{}},
+				},
+			}
+			oldCluster := &EtcdCluster{
+				Spec: EtcdClusterSpec{
+					Replicas: ptr.To(int32(1)),
+					Storage:  StorageSpec{EmptyDir: nil},
+				},
+			}
+			w, err := etcdCluster.ValidateUpdate(oldCluster)
+			gomega.Expect(w).To(gomega.BeEmpty())
+			if gomega.Expect(err).To(gomega.HaveOccurred()) {
+				statusErr := err.(*errors.StatusError)
+				gomega.Expect(statusErr.ErrStatus.Message).To(gomega.ContainSubstring("field is immutable"))
+			}
+		})
+	})
 })