Volume Health Monitoring [page]deterministic

conceptsstorage

[CSI](#gloss:csi) volume health monitoring allows CSI Drivers to detect abnormal volume conditions from the underlying storage systems and report them as events on [PVCs](#gloss:persistent-volume-claim) or [Pods](#gloss:pod).

## Volume health monitoring

Kubernetes _volume health monitoring_ is part of how Kubernetes implements the Container Storage Interface (CSI). Volume health monitoring feature is implemented in two components: an External Health Monitor controller, and the [kubelet](#gloss:kubelet).

If a CSI Driver supports Volume Health Monitoring feature from the controller side, an event will be reported on the related [PersistentVolumeClaim](#gloss:persistent-volume-claim) (PVC) when an abnormal volume condition is detected on a CSI volume.

The External Health Monitor [controller](#gloss:controller) also watches for node failure events. You can enable node failure monitoring by setting the `enable-node-watcher` flag to true. When the external health monitor detects a node failure event, the controller reports an Event will be reported on the PVC to indicate that pods using this PVC are on a failed node.

If a CSI Driver supports Volume Health Monitoring feature from the node side, an Event will be reported on every Pod using the PVC when an abnormal volume condition is detected on a CSI volume. In addition, Volume Health information is exposed as Kubelet VolumeStats metrics. A new metric kubelet_volume_stats_health_status_abnormal is added. This metric includes two labels: `namespace` and `persistentvolumeclaim`. The count is either 1 or 0. 1 indicates the volume is unhealthy, 0 indicates volume is healthy. For more information, please check [KEP](https://github.com/kubernetes/enhancements/tree/master/keps/sig-storage/1432-volume-health-monitor#kubelet-metrics-changes).

> Note: You need to enable the `CSIVolumeHealth` [feature gate](/docs/reference/command-line-tools-reference/feature-gates/) to use this feature from the node side.

See the [CSI driver documentation](https://kubernetes-csi.github.io/docs/drivers.html) to find out which CSI drivers have implemented this feature.

Sources

concepts/storage/volume-health-monitoring.md · doc — “Volume Health Monitoring”

Related (8)

references Container Storage Interface (CSI) — CSI conf=1

references Persistent Volume Claim — PVCs conf=1

references Pod — Pods conf=1

references Kubelet — kubelet conf=1

references Controller — controller conf=1

part_of Volume health monitoring — describes conf=1

part_of {{% heading "whatsnext" %}} — describes conf=1

api_for Volume — documents API object conf=1

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