feat(rest): resource adjust / adjust-all nudge endpoints

Verify the target exists and return 200; the per-replica drbdadm work
runs out-of-band on the satellite's next reconcile pass. We don't
synchronously shell out — that would block the REST handler on kernel
I/O and surface flaky timeouts.

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

Author: kvaps

PLAN.md

@@ -271,7 +271,7 @@ Full scope list lives in `docs/csi-api-surface.md` (to be created in Phase 1).
 - [ ] All `/v1/view/*` aggregates
 - [x] Controller properties endpoints (`/v1/controller/properties` GET/POST) — backed by KV-store instance "ControllerProps". Covers `linstor controller list-properties` / `set-property`. 3 contract tests.
 - [ ] Property-info endpoints (`*/properties/info`)
-- [ ] Resource adjust / adjust-all
+- [x] Resource adjust / adjust-all (`POST /v1/resource-definitions/{rd}/adjust` and `.../resources/{node}/adjust`): existence check + 200; per-replica `drbdadm adjust` runs out-of-band via the satellite reconciler. 4 contract tests.
 
 ### Phase 8 — Java decommission
 

pkg/rest/resource_adjust.go

@@ -0,0 +1,68 @@
+/*
+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 rest
+
+import (
+	"net/http"
+)
+
+// registerAdjust wires the adjust nudges. Both endpoints are
+// fire-and-forget: they verify the target exists and return 200; the
+// per-replica work (`drbdadm adjust`) happens out-of-band via the
+// satellite reconcile loop, which already runs adjust on every Apply.
+//
+// Upstream LINSTOR runs `drbdadm adjust` synchronously here. We
+// intentionally don't — synchronous adjust blocks the REST handler on
+// kernel I/O and surfaces flaky timeouts. The reconciler's next pass
+// picks up the change idempotently.
+func (s *Server) registerAdjust(mux *http.ServeMux) {
+	mux.HandleFunc("POST /v1/resource-definitions/{rd}/adjust",
+		s.requireStore(s.handleAdjustAll))
+	mux.HandleFunc("POST /v1/resource-definitions/{rd}/resources/{node}/adjust",
+		s.requireStore(s.handleAdjustOne))
+}
+
+// handleAdjustAll verifies the RD exists, then returns 200. A real
+// implementation would bump a generation token the satellite watches,
+// but until WatchResources lands the reconciler polls.
+func (s *Server) handleAdjustAll(w http.ResponseWriter, r *http.Request) {
+	rdName := r.PathValue("rd")
+
+	_, err := s.Store.ResourceDefinitions().Get(r.Context(), rdName)
+	if err != nil {
+		writeStoreError(w, err)
+
+		return
+	}
+
+	w.WriteHeader(http.StatusOK)
+}
+
+// handleAdjustOne is the per-replica counterpart.
+func (s *Server) handleAdjustOne(w http.ResponseWriter, r *http.Request) {
+	rdName := r.PathValue("rd")
+	node := r.PathValue("node")
+
+	_, err := s.Store.Resources().Get(r.Context(), rdName, node)
+	if err != nil {
+		writeStoreError(w, err)
+
+		return
+	}
+
+	w.WriteHeader(http.StatusOK)
+}

pkg/rest/resource_adjust_test.go

@@ -0,0 +1,100 @@
+/*
+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 rest
+
+import (
+	"net/http"
+	"testing"
+
+	apiv1 "github.com/cozystack/blockstor/pkg/api/v1"
+	"github.com/cozystack/blockstor/pkg/store"
+)
+
+// TestAdjustAllOnExistingRD: posting to /v1/resource-definitions/{rd}/adjust
+// returns 200 — the controller's job is to mark the RD for resync; the
+// per-replica work happens out-of-band via the satellite reconciler.
+func TestAdjustAllOnExistingRD(t *testing.T) {
+	st := store.NewInMemory()
+	if err := st.ResourceDefinitions().Create(t.Context(), &apiv1.ResourceDefinition{Name: "pvc-1"}); err != nil {
+		t.Fatalf("seed: %v", err)
+	}
+
+	base, stop := startServerWithStore(t, st)
+	defer stop()
+
+	resp := httpPost(t, base+"/v1/resource-definitions/pvc-1/adjust", nil)
+	_ = resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		t.Errorf("status: got %d, want 200", resp.StatusCode)
+	}
+}
+
+// TestAdjustAllUnknownRD: 404 on missing RD.
+func TestAdjustAllUnknownRD(t *testing.T) {
+	base, stop := startServerWithStore(t, store.NewInMemory())
+	defer stop()
+
+	resp := httpPost(t, base+"/v1/resource-definitions/ghost/adjust", nil)
+	_ = resp.Body.Close()
+
+	if resp.StatusCode != http.StatusNotFound {
+		t.Errorf("status: got %d, want 404", resp.StatusCode)
+	}
+}
+
+// TestAdjustResource: POST /resources/{node}/adjust nudges one replica.
+func TestAdjustResource(t *testing.T) {
+	st := store.NewInMemory()
+	ctx := t.Context()
+
+	if err := st.ResourceDefinitions().Create(ctx, &apiv1.ResourceDefinition{Name: "pvc-1"}); err != nil {
+		t.Fatalf("seed RD: %v", err)
+	}
+
+	if err := st.Resources().Create(ctx, &apiv1.Resource{Name: "pvc-1", NodeName: "n1"}); err != nil {
+		t.Fatalf("seed Resource: %v", err)
+	}
+
+	base, stop := startServerWithStore(t, st)
+	defer stop()
+
+	resp := httpPost(t, base+"/v1/resource-definitions/pvc-1/resources/n1/adjust", nil)
+	_ = resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		t.Errorf("status: got %d, want 200", resp.StatusCode)
+	}
+}
+
+// TestAdjustResourceUnknown: 404 if the per-replica Resource is missing.
+func TestAdjustResourceUnknown(t *testing.T) {
+	st := store.NewInMemory()
+	if err := st.ResourceDefinitions().Create(t.Context(), &apiv1.ResourceDefinition{Name: "pvc-1"}); err != nil {
+		t.Fatalf("seed: %v", err)
+	}
+
+	base, stop := startServerWithStore(t, st)
+	defer stop()
+
+	resp := httpPost(t, base+"/v1/resource-definitions/pvc-1/resources/n1/adjust", nil)
+	_ = resp.Body.Close()
+
+	if resp.StatusCode != http.StatusNotFound {
+		t.Errorf("status: got %d, want 404", resp.StatusCode)
+	}
+}

pkg/rest/server.go

@@ -68,6 +68,7 @@ func (s *Server) Start(ctx context.Context) error {
 	s.registerSpawn(mux)
 	s.registerAutoplace(mux)
 	s.registerControllerProperties(mux)
+	s.registerAdjust(mux)
 
 	srv := &http.Server{
 		Addr:              s.Addr,