pvc-autoresizer resizes PersistentVolumeClaims (PVCs) when the free amount of storage is below the threshold. It queries the volume usage metrics from Prometheus that collects metrics from kubelet.

Status: beta

• Kubernetes: 1.24, 1.23, 1.22

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

• implement Volume Expansion.
• implement NodeGetVolumeStats

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

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

pvc-autoresizer can be deployed to a Kubernetes cluster via helm:

helm repo add pvc-autoresizer https://topolvm.github.io/pvc-autoresizer/
helm install --create-namespace --namespace pvc-autoresizer pvc-autoresizer pvc-autoresizer/pvc-autoresizer --set "controller.args.prometheusURL=<YOUR PROMETHEUS ENDPOINT>"

See the Chart README.md for detailed documentation on the Helm Chart.

To allow auto volume expansion, the StorageClass of PVC need to allow volume expansion and have resize.topolvm.io/enabled: "true" annotation. The annotation may be omitted if you give --no-annotation-check command-line flag to pvc-autoresizer executable.

kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: topolvm-provisioner
  annotations:
    resize.topolvm.io/enabled: "true"
provisioner: topolvm.cybozu.com
allowVolumeExpansion: true

To allow auto volume expansion, the PVC to be resized need to specify the upper limit of volume size with the annotation resize.topolvm.io/storage_limit. The PVC must have volumeMode: Filesystem too. You can also set the upper limit of volume size with .spec.resources.limits.storage, but it is deprecated. If both are present, the annotation takes precedence.

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: topolvm-pvc
  namespace: default
  annotations:
    resize.topolvm.io/storage_limit: 100Gi
spec:
  accessModes:
  - ReadWriteOnce
  volumeMode: Filesystem
  resources:
    requests:
      storage: 30Gi
  storageClassName: topolvm-provisioner

The PVC can optionally have resize.topolvm.io/threshold, resize.topolvm.io/inodes-threshold and resize.topolvm.io/increase annotations. (If they are not given, the default value is 10%.)

When the amount of free space of the volume is below resize.topolvm.io/threshold or the number of free inodes is below resize.topolvm.io/inodes-threshold, .spec.resources.requests.storage is increased by resize.topolvm.io/increase.

If resize.topolvm.io/increase is given as a percentage, the value is calculated as the current spec.resources.requests.storage value multiplied by the annotation value.

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: topolvm-pvc
  namespace: default
  annotations:
    resize.topolvm.io/storage_limit: 100Gi
    resize.topolvm.io/threshold: 20%
    resize.topolvm.io/inodes-threshold: 20%
    resize.topolvm.io/increase: 20Gi
spec:
  <snip>

Container images are available on ghcr.io
Please note that the images on quay.io are currently deprecated and will no longer be available in the future.

pvcautoresizer_kubernetes_client_fail_total is a counter that indicates how many API requests to kube-api server are failed.

pvcautoresizer_metrics_client_fail_total is a counter that indicates how many API requests to metrics server(e.g. prometheus) are failed.

pvcautoresizer_loop_seconds_total is a counter that indicates the sum of seconds spent on volume expansion processing loops.

pvcautoresizer_success_resize_total is a counter that indicates how many volume expansion processing resizes succeed.

pvcautoresizer_failed_resize_total is a counter that indicates how many volume expansion processing resizes fail.

pvcautoresizer_limit_reached_total is a counter that indicates how many storage limit was reached.