KubeDB

By AppsCode

CONTACT SALES

New to KubeDB? Please start here.

Milvus Volume Expansion

This guide will show you how to use the KubeDB Ops-manager operator to expand the persistent volumes of a Milvus database.

Before You Begin

  • You should be familiar with the following KubeDB concepts:

  • Complete the dependency setup from Prepare Dependencies. It installs MinIO and creates the object-storage secrets (milvus-storage-config for milvus-standalone, milvus-cluster-storage-config for milvus-cluster).

  • The PVC’s StorageClass must support volume expansion (allowVolumeExpansion: true). The base examples use local-path, which does not support expansion, so this guide uses longhorn-custom:

    $ kubectl get sc longhorn-custom -o jsonpath='{.allowVolumeExpansion}'
true

Note: The yaml files used in this tutorial are stored in docs/guides/milvus/volume-expansion/yamls folder in GitHub repository kubedb/docs.

Volume Expansion — Standalone Milvus

Deploy a standalone Milvus on an expansion-capable StorageClass (here longhorn-custom) with a 1Gi volume. volume-expansion/yamls/milvus-standalone.yaml is the standalone quickstart manifest with storageClassName: longhorn-custom:

If you deleted a Milvus of the same name in an earlier guide, delete its object-storage prefix first, as shown in Prepare Dependencies. Otherwise the new database can hang in Provisioning.

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2026.10.12/docs/guides/milvus/volume-expansion/yamls/milvus-standalone.yaml
milvus.kubedb.com/milvus-standalone created

$ kubectl get milvuses.kubedb.com -n demo milvus-standalone -w

$ kubectl get pvc -n demo -l app.kubernetes.io/instance=milvus-standalone -o custom-columns=NAME:.metadata.name,SIZE:.status.capacity.storage,SC:.spec.storageClassName
NAME                       SIZE   SC
data-milvus-standalone-0   1Gi    longhorn-custom

Offline Volume Expansion

volume-expansion-offline-standalone.yaml

apiVersion: ops.kubedb.com/v1alpha1
kind: MilvusOpsRequest
metadata:
  name: volume-expansion-offline
  namespace: demo
spec:
  type: VolumeExpansion
  databaseRef:
    name: milvus-standalone
  volumeExpansion:
    node: 4Gi
    mode: Offline

Here, spec.volumeExpansion.node is the standalone target size, and mode: Offline takes the pod down while the volume is resized.

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2026.10.12/docs/guides/milvus/volume-expansion/yamls/volume-expansion-offline-standalone.yaml
milvusopsrequest.ops.kubedb.com/volume-expansion-offline created

$ kubectl get milvusopsrequest volume-expansion-offline -n demo
NAME                       TYPE              STATUS       AGE
volume-expansion-offline   VolumeExpansion   Successful   2m

The volume is now 4Gi:

$ kubectl get pvc -n demo -l app.kubernetes.io/instance=milvus-standalone -o custom-columns=NAME:.metadata.name,SIZE:.status.capacity.storage,SC:.spec.storageClassName
NAME                       SIZE   SC
data-milvus-standalone-0   4Gi    longhorn-custom

Online Volume Expansion

Online expansion grows the volume without taking the pod down. The volume is already 4Gi after the offline step above, so this request grows it to 6Gi. (A request for the current size is accepted and reported Successful without changing anything.)

volume-expansion-online-standalone.yaml

apiVersion: ops.kubedb.com/v1alpha1
kind: MilvusOpsRequest
metadata:
  name: volume-expansion-online
  namespace: demo
spec:
  type: VolumeExpansion
  databaseRef:
    name: milvus-standalone
  volumeExpansion:
    node: 6Gi
    mode: Online

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2026.10.12/docs/guides/milvus/volume-expansion/yamls/volume-expansion-online-standalone.yaml
milvusopsrequest.ops.kubedb.com/volume-expansion-online created

$ kubectl get milvusopsrequest volume-expansion-online -n demo
NAME                      TYPE              STATUS       AGE
volume-expansion-online   VolumeExpansion   Successful   2m4s

The volume has grown to 6Gi, and the database spec reflects the new size:

$ kubectl get pvc -n demo -l app.kubernetes.io/instance=milvus-standalone -o custom-columns=NAME:.metadata.name,SIZE:.status.capacity.storage,SC:.spec.storageClassName
NAME                       SIZE   SC
data-milvus-standalone-0   6Gi    longhorn-custom

$ kubectl get milvuses.kubedb.com milvus-standalone -n demo -o jsonpath='{.spec.storage.resources.requests.storage}'
6Gi

Volume Expansion — Distributed Milvus

For a distributed Milvus, volume expansion targets streamingnode — the only distributed role that carries a persistent volume. Point spec.databaseRef.name at milvus-cluster and use the streamingnode key.

Deploy a distributed Milvus with two streamingnode replicas on longhorn-custom, each with a 1Gi volume. volume-expansion/yamls/milvus-distributed.yaml is the distributed quickstart manifest with storageClassName: longhorn-custom and streamingnode.replicas: 2:

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2026.10.12/docs/guides/milvus/volume-expansion/yamls/milvus-distributed.yaml
milvus.kubedb.com/milvus-cluster created

$ kubectl get milvuses.kubedb.com -n demo milvus-cluster -w

The distributed OpsRequests reuse the names of the standalone ones, so delete the standalone OpsRequests first:

$ kubectl delete milvusopsrequest -n demo volume-expansion-offline volume-expansion-online

volume-expansion-online-distributed.yaml

apiVersion: ops.kubedb.com/v1alpha1
kind: MilvusOpsRequest
metadata:
  name: volume-expansion-online
  namespace: demo
spec:
  type: VolumeExpansion
  databaseRef:
    name: milvus-cluster
  volumeExpansion:
    streamingnode: 4Gi
    mode: Online

(An Offline variant — volume-expansion-offline-distributed.yaml — uses streamingnode: 3Gi with mode: Offline.)

The operator expands the PVC of every streamingnode replica, one replica at a time. Starting from 1Gi on longhorn-custom, an offline expansion to 3Gi followed by an online expansion to 4Gi. Apply the online request only after the offline one is Successful:

# offline: streamingnode 1Gi -> 3Gi
$ kubectl apply -f https://github.com/kubedb/docs/raw/v2026.10.12/docs/guides/milvus/volume-expansion/yamls/volume-expansion-offline-distributed.yaml
milvusopsrequest.ops.kubedb.com/volume-expansion-offline created

$ kubectl get milvusopsrequest volume-expansion-offline -n demo
NAME                       TYPE              STATUS       AGE
volume-expansion-offline   VolumeExpansion   Successful   ...

# online: streamingnode 3Gi -> 4Gi
$ kubectl apply -f https://github.com/kubedb/docs/raw/v2026.10.12/docs/guides/milvus/volume-expansion/yamls/volume-expansion-online-distributed.yaml
milvusopsrequest.ops.kubedb.com/volume-expansion-online created

$ kubectl get pvc -n demo -l app.kubernetes.io/instance=milvus-cluster -o custom-columns=NAME:.metadata.name,SIZE:.status.capacity.storage
NAME                                  SIZE
data-milvus-cluster-streamingnode-0   4Gi
data-milvus-cluster-streamingnode-1   4Gi

Both streamingnode replicas are expanded. The stateless roles (mixcoord, datanode, querynode, proxy) have no persistent volume and are unaffected.

On a single-node test cluster, offline expansion of a distributed role can take a few minutes because the pods are restarted after the resize.

Cleaning up

$ kubectl delete milvusopsrequest -n demo volume-expansion-offline volume-expansion-online
$ kubectl patch -n demo milvus.kubedb.com milvus-standalone -p '{"spec":{"deletionPolicy":"WipeOut"}}' --type="merge"
$ kubectl patch -n demo milvus.kubedb.com milvus-cluster -p '{"spec":{"deletionPolicy":"WipeOut"}}' --type="merge"
$ kubectl delete milvus.kubedb.com -n demo milvus-standalone milvus-cluster
$ kubectl delete ns demo

Next Steps

What's on this Page

Search
Improve This Page