pvc-autoresizer

pvc-autoresizer

pvc-autoresizer is an automatic volume resizer that edits PVCs if they have less than the specified amount of free filesystem capacity.

Target CSI Drivers

pvc-autoresizer supports CSI Drivers that meet the following requirements:

• implement Volume Expansion.
• implement NodeGetVolumeStats

Prepare

pvc-autoresizer behaves based on the metrics that prometheus collects from kubelet.

Please refer to the following pages to set up Prometheus:

• Installation | Prometheus

In addition, configure scraping as follows:

• Monitoring with Prometheus | TopoLVM

Installation

Specify the Prometheus URL to pvc-autoresizer argument as --prometheus-url.

pvc-autoresizer can be deployed to a Kubernetes cluster via kustomize and kubectl:

kustomize build ./config/default | kubectl apply -f -

How to use

The StorageClass of the PVC to be resized must have resize.topolvm.io/enabled: "true" annotation.

kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: topolvm-provisioner
  annotations:
    resize.topolvm.io/enabled: "true" 
provisioner: topolvm.cybozu.com
parameters:
  "csi.storage.k8s.io/fstype": "xfs"
volumeBindingMode: WaitForFirstConsumer
allowVolumeExpansion: true

The PVC to be resized must have .spec.resources.limits.storage and must be volumeMode: Filesystem. The PVC can optionally have resize.topolvm.io/threshold and resize.topolvm.io/increase annotations. (If they are not given, the default value is 10%.)

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: topolvm-pvc
  annotations:
    resize.topolvm.io/threshold: 20%
    resize.topolvm.io/increase: 20Gi
spec:
  accessModes:
  - ReadWriteOnce
  volumeMode: Filesystem
  resources:
    requests:
      storage: 30Gi
    limits:
      storage: 100Gi
  storageClassName: topolvm-provisioner

When the amount of free space of the volume is smaller than resize.topolvm.io/threshold, the .spec.resources.requests.storage size will be increased by resize.topolvm.io/increase. The maximum size is specified by .spec.resources.limits.storage.

Container images

Container images are available on Quay.io