feat: ResourceGroup CRD + /v1/resource-groups CRUD

Phase 2 second slice: linstor-csi creates one ResourceGroup per Kubernetes
StorageClass and Spawns ResourceDefinitions from it; this is the gateway
to volume provisioning.

- pkg/api/v1/resource_group.go: wire-shape ResourceGroup, VolumeGroup,
  AutoSelectFilter, ResourceGroupSpawn (matching upstream golinstor).
- api/v1alpha1/resourcegroup_types.go: CRD with Description, Props,
  PeerSlots, SelectFilter (placement constraints), VolumeGroups.
- pkg/store/k8s/resource_groups.go: CRD <-> wire conversion + CRUD.
- pkg/store/storetest: 8-case ResourceGroupStore suite, both InMemory and
  k8s/envtest implementations green.
- pkg/rest/resource_groups.go: 5 handlers (list/get/create/update/delete);
  Spawn lands when ResourceDefinition does (CSI MVP scope).
- pkg/rest/resource_groups_test.go: 6 contract tests via golinstor
  (round-trip, conflict→409, get-missing→404, delete-cascades,
  no-store→503).

Spawn / adjust / query-size-info / volume-groups still ⬜ in
docs/csi-api-surface.md — those depend on ResourceDefinition.

Co-Authored-By: Claude <noreply@anthropic.com>
Signed-off-by: Andrei Kvapil <kvapss@gmail.com>

Author: kvaps

.golangci.yml

@@ -118,6 +118,17 @@ linters:
           - goconst
           - noinlineerr
         path: _test\.go
+      # k8s store implementations follow the same Get/Create/Update/Delete
+      # template per resource — duplication is the point and is shared via
+      # the storetest suite already.
+      - linters:
+          - dupl
+        path: pkg/store/k8s/
+      # REST handlers follow the same Get/Create/Update/Delete shape per
+      # resource for the same reason.
+      - linters:
+          - dupl
+        path: pkg/rest/
       # storetest is a shared test suite imported by both InMemory and k8s
       # store tests. It contains test code, just not in _test.go files, so
       # the same exclusions apply.
@@ -168,6 +179,8 @@ linters:
           - gocritic
           - noinlineerr
           - wsl_v5
+          - cyclop
+          - gocyclo
         path: cmd/main.go
       # api/v1alpha1 and internal/controller are kubebuilder scaffold; the
       # boilerplate (dot-imports for ginkgo/gomega, generated DeepCopy globals,

PROJECT

@@ -25,4 +25,12 @@ resources:
   kind: StoragePool
   path: github.com/cozystack/blockstor/api/v1alpha1
   version: v1alpha1
+- api:
+    crdVersion: v1
+  controller: true
+  domain: blockstor.io
+  group: blockstor.io
+  kind: ResourceGroup
+  path: github.com/cozystack/blockstor/api/v1alpha1
+  version: v1alpha1
 version: "3"

api/v1alpha1/resourcegroup_types.go

@@ -0,0 +1,127 @@
+/*
+Copyright 2026 Cozystack contributors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package v1alpha1
+
+import (
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+)
+
+// ResourceGroupSpec is the desired state of a LINSTOR ResourceGroup — the
+// template linstor-csi creates per StorageClass and Spawns ResourceDefinitions
+// from. Mirrors the upstream `ResourceGroup` shape (modulo k8s naming).
+type ResourceGroupSpec struct {
+	// description is human-readable.
+	// +optional
+	Description string `json:"description,omitempty"`
+
+	// props is the LINSTOR property map for this resource group.
+	// +optional
+	Props map[string]string `json:"props,omitempty"`
+
+	// peerSlots is the DRBD peer-slot count baked into spawned resources.
+	// +optional
+	PeerSlots int32 `json:"peerSlots,omitempty"`
+
+	// selectFilter constrains autoplacer when spawning resources from this
+	// group.
+	// +optional
+	SelectFilter ResourceGroupSelectFilter `json:"selectFilter,omitzero"`
+
+	// volumeGroups templates the per-volume props/flags for spawned resources.
+	// +optional
+	VolumeGroups []ResourceGroupVolumeGroup `json:"volumeGroups,omitempty"`
+}
+
+// ResourceGroupSelectFilter is the in-CRD shape of LINSTOR's AutoSelectFilter.
+type ResourceGroupSelectFilter struct {
+	// +optional
+	PlaceCount int32 `json:"placeCount,omitempty"`
+	// +optional
+	StoragePool string `json:"storagePool,omitempty"`
+	// +optional
+	StoragePoolList []string `json:"storagePoolList,omitempty"`
+	// +optional
+	StoragePoolDisklessList []string `json:"storagePoolDisklessList,omitempty"`
+	// +optional
+	NodeNameList []string `json:"nodeNameList,omitempty"`
+	// +optional
+	ReplicasOnSame []string `json:"replicasOnSame,omitempty"`
+	// +optional
+	ReplicasOnDifferent []string `json:"replicasOnDifferent,omitempty"`
+	// +optional
+	NotPlaceWithRsc []string `json:"notPlaceWithRsc,omitempty"`
+	// +optional
+	NotPlaceWithRscRegex string `json:"notPlaceWithRscRegex,omitempty"`
+	// +optional
+	LayerStack []string `json:"layerStack,omitempty"`
+	// +optional
+	ProviderList []string `json:"providerList,omitempty"`
+	// +optional
+	DisklessOnRemaining bool `json:"disklessOnRemaining,omitempty"`
+}
+
+// ResourceGroupVolumeGroup is one volume's template inside a ResourceGroup.
+type ResourceGroupVolumeGroup struct {
+	VolumeNumber int32 `json:"volumeNumber"`
+	// +optional
+	Props map[string]string `json:"props,omitempty"`
+	// +optional
+	Flags []string `json:"flags,omitempty"`
+}
+
+// ResourceGroupStatus is the observed state.
+type ResourceGroupStatus struct {
+	// conditions represent the current state of the ResourceGroup.
+	// +listType=map
+	// +listMapKey=type
+	// +optional
+	Conditions []metav1.Condition `json:"conditions,omitempty"`
+}
+
+// +kubebuilder:object:root=true
+// +kubebuilder:subresource:status
+// +kubebuilder:resource:scope=Cluster
+
+// ResourceGroup is the Schema for the resourcegroups API
+type ResourceGroup struct {
+	metav1.TypeMeta `json:",inline"`
+
+	// metadata is a standard object metadata
+	// +optional
+	metav1.ObjectMeta `json:"metadata,omitzero"`
+
+	// spec defines the desired state of ResourceGroup
+	// +required
+	Spec ResourceGroupSpec `json:"spec"`
+
+	// status defines the observed state of ResourceGroup
+	// +optional
+	Status ResourceGroupStatus `json:"status,omitzero"`
+}
+
+// +kubebuilder:object:root=true
+
+// ResourceGroupList contains a list of ResourceGroup
+type ResourceGroupList struct {
+	metav1.TypeMeta `json:",inline"`
+	metav1.ListMeta `json:"metadata,omitzero"`
+	Items           []ResourceGroup `json:"items"`
+}
+
+func init() {
+	SchemeBuilder.Register(&ResourceGroup{}, &ResourceGroupList{})
+}

api/v1alpha1/zz_generated.deepcopy.go

@@ -200,6 +200,13 @@ func main() {
 		setupLog.Error(err, "Failed to create controller", "controller", "storagepool")
 		os.Exit(1)
 	}
+	if err := (&controller.ResourceGroupReconciler{
+		Client: mgr.GetClient(),
+		Scheme: mgr.GetScheme(),
+	}).SetupWithManager(mgr); err != nil {
+		setupLog.Error(err, "Failed to create controller", "controller", "resourcegroup")
+		os.Exit(1)
+	}
 	// +kubebuilder:scaffold:builder
 
 	if err := mgr.AddHealthzCheck("healthz", healthz.Ping); err != nil {