Optionally provide ordinal for specific pod snapshotting

api/v1alpha1/scheduledvolumesnapshot_types.go

@@ -99,6 +99,11 @@ type LocalFullNodeRef struct {
 	// DEPRECATED: CosmosFullNode must be in the same namespace as the ScheduledVolumeSnapshot. This field is ignored.
 	// +optional
 	Namespace string `json:"namespace"`
+
+	// Index of the pod to snapshot. If not provided, will do any pod in the CosmosFullNode.
+	// Useful when snapshots are local to the same node as the pod, requiring snapshots across multiple pods/nodes.
+	// +optional
+	Ordinal *int32 `json:"index"`
 }
 
 // ScheduledVolumeSnapshotStatus defines the observed state of ScheduledVolumeSnapshot

internal/volsnapshot/vol_snapshot_control.go

@@ -67,7 +67,23 @@ func (control VolumeSnapshotControl) FindCandidate(ctx context.Context, crd *cos
 		return Candidate{}, fmt.Errorf("%d or more pods must be in-sync to prevent downtime, found %d in-sync", minAvail, availCount)
 	}
 
-	pod := synced[0]
+	var pod *corev1.Pod
+
+	if crd.Spec.FullNodeRef.Ordinal != nil {
+		podIndex := *crd.Spec.FullNodeRef.Ordinal
+		podIndexStr := fmt.Sprintf("%d", podIndex)
+		for _, p := range synced {
+			if p.Annotations["app.kubernetes.io/ordinal"] == podIndexStr {
+				pod = p
+				break
+			}
+		}
+		if pod == nil {
+			return Candidate{}, fmt.Errorf("in-sync pod with index %d not found", podIndex)
+		}
+	} else {
+		pod = synced[0]
+	}
 
 	return Candidate{
 		PodLabels: pod.Labels,

internal/volsnapshot/vol_snapshot_control_test.go

@@ -123,6 +123,75 @@ func TestVolumeSnapshotControl_FindCandidate(t *testing.T) {
 		require.Equal(t, candidate.Labels, got.PodLabels)
 	})
 
+	t.Run("happy path with index", func(t *testing.T) {
+		pods := make([]corev1.Pod, 3)
+		for i := range pods {
+			pods[i].Status.Conditions = []corev1.PodCondition{readyCondition}
+		}
+		var mClient mockPodClient
+		mClient.Items = pods
+
+		var fullnodeCRD cosmosv1.CosmosFullNode
+		fullnodeCRD.Name = fullNodeName
+		// Purposefully using PodBuilder to cross-test any breaking changes in PodBuilder which affects
+		// finding the PVC name.
+		candidate, err := fullnode.NewPodBuilder(&fullnodeCRD).WithOrdinal(1).Build()
+		require.NoError(t, err)
+
+		candidate.Annotations["app.kubernetes.io/ordinal"] = "1"
+
+		control := NewVolumeSnapshotControl(&mClient, mockPodFilter{
+			SyncedPodsFn: func(ctx context.Context, controller client.ObjectKey) []*corev1.Pod {
+				require.Equal(t, namespace, controller.Namespace)
+				require.Equal(t, fullNodeName, controller.Name)
+				return []*corev1.Pod{candidate, new(corev1.Pod), new(corev1.Pod)}
+			},
+		})
+
+		indexCRD := crd.DeepCopy()
+		index := int32(1)
+		indexCRD.Spec.FullNodeRef.Ordinal = &index
+
+		got, err := control.FindCandidate(ctx, indexCRD)
+		require.NoError(t, err)
+
+		require.Equal(t, "cosmoshub-1", got.PodName)
+		require.Equal(t, "pvc-cosmoshub-1", got.PVCName)
+		require.NotEmpty(t, got.PodLabels)
+		require.Equal(t, candidate.Labels, got.PodLabels)
+	})
+
+	t.Run("index not available", func(t *testing.T) {
+		pods := make([]corev1.Pod, 3)
+		for i := range pods {
+			pods[i].Status.Conditions = []corev1.PodCondition{readyCondition}
+		}
+		var mClient mockPodClient
+		mClient.Items = pods
+
+		var fullnodeCRD cosmosv1.CosmosFullNode
+		fullnodeCRD.Name = fullNodeName
+		// Purposefully using PodBuilder to cross-test any breaking changes in PodBuilder which affects
+		// finding the PVC name.
+		candidate, err := fullnode.NewPodBuilder(&fullnodeCRD).WithOrdinal(1).Build()
+		require.NoError(t, err)
+
+		control := NewVolumeSnapshotControl(&mClient, mockPodFilter{
+			SyncedPodsFn: func(ctx context.Context, controller client.ObjectKey) []*corev1.Pod {
+				require.Equal(t, namespace, controller.Namespace)
+				require.Equal(t, fullNodeName, controller.Name)
+				return []*corev1.Pod{candidate, new(corev1.Pod), new(corev1.Pod)}
+			},
+		})
+
+		indexCRD := crd.DeepCopy()
+		index := int32(2)
+		indexCRD.Spec.FullNodeRef.Ordinal = &index
+
+		_, err = control.FindCandidate(ctx, indexCRD)
+		require.ErrorContains(t, err, "in-sync pod with index 2 not found")
+	})
+
 	t.Run("custom min available", func(t *testing.T) {
 		var pod corev1.Pod
 		pod.Name = "found-me"