KubeDB

By AppsCode

CONTACT SALES
You are looking at the documentation of a prior release. To read the documentation of the latest release, please visit here.

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, creates the my-release-minio secret, and installs the etcd operator required by Milvus.

  • 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:

$ 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/v2026.7.10/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 example file requests node: 4Gi; since the volume is already 4Gi after the offline step above, this walkthrough requests 6Gi to demonstrate a second (online) expansion:

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 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:

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. Starting from 1Gi on longhorn-custom, an offline expansion to 3Gi followed by an online expansion to 4Gi:

# offline: streamingnode 1Gi -> 3Gi
$ kubectl get milvusopsrequest volume-expansion-offline -n demo
NAME                       TYPE              STATUS       AGE
volume-expansion-offline   VolumeExpansion   Successful   ...

# online: streamingnode 3Gi -> 4Gi
$ 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 delete milvus.kubedb.com -n demo milvus-standalone
$ kubectl delete ns demo

Next Steps

What's on this Page

Search
Improve This Page