fix: enable MultiOrch placement defaulting

Implements logic in `reconcileDatabases` to automatically populate
`MultiOrch.Cells` if it is empty. It defaults to the set of all unique
cells defined in the Shard's pools, ensuring the orchestration layer
is deployed alongside data nodes as per the design specification.

Adds regression test "Create: MultiOrch Placement Defaulting".

Author: fernando-villalba

pkg/cluster-handler/controller/multigrescluster/multigrescluster_controller.go

@@ -3,6 +3,7 @@ package multigrescluster
 import (
 	"context"
 	"fmt"
+	"sort"
 	"time"
 
 	appsv1 "k8s.io/api/apps/v1"
@@ -202,6 +203,7 @@ func (r *MultigresClusterReconciler) reconcileGlobalComponents(ctx context.Conte
 					Labels: map[string]string{"app": "multiadmin", "multigres.com/cluster": cluster.Name},
 				},
 				Spec: corev1.PodSpec{
+					ImagePullSecrets: cluster.Spec.Images.ImagePullSecrets,
 					Containers: []corev1.Container{
 						{
 							Name:      "multiadmin",
@@ -325,6 +327,24 @@ func (r *MultigresClusterReconciler) reconcileDatabases(ctx context.Context, clu
 
 				orch, pools := MergeShardConfig(tpl, shard.Overrides, shard.Spec)
 
+				// Default MultiOrch Cells if empty (Consensus safety)
+				// If 'cells' is empty, it defaults to all cells where pools are defined.
+				if len(orch.Cells) == 0 {
+					uniqueCells := make(map[string]bool)
+					for _, pool := range pools {
+						for _, cell := range pool.Cells {
+							uniqueCells[string(cell)] = true
+						}
+					}
+					for c := range uniqueCells {
+						orch.Cells = append(orch.Cells, multigresv1alpha1.CellName(c))
+					}
+					// Sort for deterministic output
+					sort.Slice(orch.Cells, func(i, j int) bool {
+						return string(orch.Cells[i]) < string(orch.Cells[j])
+					})
+				}
+
 				resolvedShards = append(resolvedShards, multigresv1alpha1.ShardResolvedSpec{
 					Name:      shard.Name,
 					MultiOrch: orch,

pkg/cluster-handler/controller/multigrescluster/multigrescluster_controller_test.go

@@ -258,6 +258,65 @@ func TestMultigresClusterReconciler_Reconcile(t *testing.T) {
 				}
 			},
 		},
+		{
+			name: "Create: MultiOrch Placement Defaulting",
+			cluster: func() *multigresv1alpha1.MultigresCluster {
+				c := baseCluster.DeepCopy()
+				c.Spec.TemplateDefaults.ShardTemplate = "" // Ensure no default template interferes
+				// Define a database with explicit pools containing cells
+				c.Spec.Databases = []multigresv1alpha1.DatabaseConfig{
+					{
+						Name: "db-defaulting",
+						TableGroups: []multigresv1alpha1.TableGroupConfig{
+							{
+								Name: "tg1",
+								Shards: []multigresv1alpha1.ShardConfig{
+									{
+										Name: "0",
+										Spec: &multigresv1alpha1.ShardInlineSpec{
+											// MultiOrch Cells explicitly EMPTY
+											MultiOrch: multigresv1alpha1.MultiOrchSpec{
+												StatelessSpec: multigresv1alpha1.StatelessSpec{Replicas: ptr.To(int32(1))},
+											},
+											Pools: map[string]multigresv1alpha1.PoolSpec{
+												"pool-a": {Cells: []multigresv1alpha1.CellName{"zone-a"}},
+												"pool-b": {Cells: []multigresv1alpha1.CellName{"zone-b"}},
+											},
+										},
+									},
+								},
+							},
+						},
+					},
+				}
+				return c
+			}(),
+			existingObjects: []client.Object{coreTpl, cellTpl},
+			expectError:     false,
+			validate: func(t *testing.T, c client.Client) {
+				ctx := context.Background()
+				// Fetch the child TableGroup (which holds the resolved shard spec)
+				tgName := clusterName + "-db-defaulting-tg1"
+				tg := &multigresv1alpha1.TableGroup{}
+				if err := c.Get(ctx, types.NamespacedName{Name: tgName, Namespace: namespace}, tg); err != nil {
+					t.Fatal(err)
+				}
+
+				if len(tg.Spec.Shards) != 1 {
+					t.Fatalf("Expected 1 shard, got %d", len(tg.Spec.Shards))
+				}
+
+				orchCells := tg.Spec.Shards[0].MultiOrch.Cells
+				if len(orchCells) != 2 {
+					t.Errorf("MultiOrch should default to 2 cells, got %d: %v", len(orchCells), orchCells)
+				}
+
+				// Check content (order is sorted by controller)
+				if string(orchCells[0]) != "zone-a" || string(orchCells[1]) != "zone-b" {
+					t.Errorf("MultiOrch cells mismatch. Got %v, Want [zone-a zone-b]", orchCells)
+				}
+			},
+		},
 		{
 			name: "Create: Inline Etcd",
 			cluster: func() *multigresv1alpha1.MultigresCluster {