Liveness Probe

The liveness probe is a sidecar container that exposes an HTTP /healthz endpoint, which serves as kubelet's livenessProbe hook to monitor health of a CSI driver.

The liveness probe uses Probe() call to check the CSI driver is healthy. See CSI spec for more information about Probe API call. Container Storage Interface (CSI)

Compatibility

This information reflects the head of this branch.

Compatible with CSI Version	Container Image	Min K8s Version
CSI Spec v1.0.0	registry.k8s.io/sig-storage/livenessprobe	1.13

Usage

See hostpath-with-livenessprobe.yaml for example how to use the liveness probe with a CSI driver. Notice that actual livenessProbe is set on the container with the CSI driver. This way, Kubernetes restarts the CSI driver container when the probe fails. The liveness probe sidecar container only provides the HTTP endpoint for the probe and does not contain livenessProbe section by itself.

kind: Pod
spec:
  containers:
  # Container with CSI driver
  - name: hostpath-driver
    image: quay.io/k8scsi/hostpathplugin:v0.2.0
    # Defining port which will be used to GET plugin health status
    # 9808 is default, but can be changed.
    ports:
    - containerPort: 9808
      name: healthz
      protocol: TCP
    # The probe
    livenessProbe:
      failureThreshold: 5
      httpGet:
        path: /healthz
        port: healthz
      initialDelaySeconds: 10
      timeoutSeconds: 3
      periodSeconds: 2
    volumeMounts:
    - mountPath: /csi
      name: socket-dir
  # ...
  # The liveness probe sidecar container
  - name: liveness-probe
    imagePullPolicy: Always
    image: registry.k8s.io/sig-storage/livenessprobe:v2.7.0
    args:
    - --csi-address=/csi/csi.sock
    volumeMounts:
    - mountPath: /csi
      name: socket-dir
    # ...

Command line options

Recommended optional arguments

• --csi-address <path to CSI socket>: This is the path to the CSI driver socket inside the pod that the external-provisioner container will use to issue CSI operations (/run/csi/socket is used by default).

Other recognized arguments

• --health-port <number>: TCP ports for listening for healthz requests (default "9808")

• --probe-timeout <duration>: Maximum duration of single Probe() call (default "1s").

• --metrics-address <port>: The TCP network address where the prometheus metrics endpoint will listen (example: :8080). The default is empty string, which means metrics endpoint is disabled.

• --metrics-path <path>: The HTTP path where prometheus metrics will be exposed. Default is /metrics."

• --http-endpoint <endpoint>: The TCP network address where the HTTP server for diagnostics, including CSI driver health check and metrics. The default is empty string, which means the server is disabled.

• All glog / klog arguments are supported, such as -v <log level> or -alsologtostderr.

Community, discussion, contribution, and support

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