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:

  • An object-storage secret named my-release-minio must exist in the demo namespace.

  • 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/v2026.6.19/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