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| reviewers | title | content_type | ||||
|---|---|---|---|---|---|---|
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Volume Health Monitoring | concept |
{{< feature-state for_k8s_version="v1.21" state="alpha" >}}
{{< glossary_tooltip text="CSI" term_id="csi" >}} volume health monitoring allows CSI Drivers to detect abnormal volume conditions from the underlying storage systems and report them as events on {{< glossary_tooltip text="PVCs" term_id="persistent-volume-claim" >}} or {{< glossary_tooltip text="Pods" term_id="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 {{< glossary_tooltip term_id="kubelet" text="kubelet" >}}.
If a CSI Driver supports Volume Health Monitoring feature from the controller side, an event will be reported on the related {{< glossary_tooltip text="PersistentVolumeClaim" term_id="persistent-volume-claim" >}} (PVC) when an abnormal volume condition is detected on a CSI volume.
The External Health Monitor {{< glossary_tooltip text="controller" term_id="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.
{{< note >}}
You need to enable the CSIVolumeHealth feature gate to use this feature from the node side.
{{< /note >}}
{{% heading "whatsnext" %}}
See the CSI driver documentation to find out which CSI drivers have implemented this feature.